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Document and Entity Information - shares	3 Months Ended
Document and Entity Information - shares	Mar. 31, 2019	May 08, 2019
Document and Entity Information
Entity Registrant Name	Quanterix Corp
Entity Central Index Key	0001503274
Document Type	10-Q
Document Period End Date	Mar. 31, 2019
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		22,596,122
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1

Condensed Consolidated Balance Sheet - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 33,972	$ 44,429
Accounts receivable (less reserve for doubtful accounts of $50 and $36 as of March 31, 2019 and December 31, 2018; including $23 and $48 from related parties as of March 31, 2019 and December 31, 2018, respectively)	7,303	6,792
Inventory	7,742	5,945
Prepaid expenses and other current assets	2,502	2,330
Total current assets	51,519	59,496
Restricted cash	1,019	1,000
Property and equipment, net	8,582	2,923
Intangible assets, net	2,198	2,348
Goodwill	1,308	1,308
Other non-current assets	550	536
Total assets	65,176	67,611
Current liabilities:
Accounts payable (including $0 and $36 to related parties as of March 31, 2019 and December 31, 2018, respectively)	3,789	5,110
Accrued compensation and benefits	3,480	4,449
Other accrued expenses (including $240 and $226 to related parties as of March 31, 2019 and December 31, 2018, respectively)	3,744	3,129
Deferred revenue (including $29 and $33 with related parties as of March 31, 2019 and December 31, 2018, respectively)	5,484	5,437
Current portion of long term debt	75
Other current liabilities	26
Total current liabilities	16,598	18,125
Deferred revenue, net of current portion	431	520
Long term debt, net of current portion	7,572	7,623
Other non-current liabilities	6,360	278
Total liabilities	30,961	26,546
Commitments and contingencies (Note 11)
Stockholders' equity:
Common stock, $0.001 par value: Authorized-120,000,000 shares as of March 31, 2019 and December 31, 2018; issued and outstanding-22,491,447 and 22,369,036 shares as of March 31, 2019 and December 31, 2018, respectively	23	22
Additional paid-in capital	219,045	216,931
Accumulated deficit	(184,853)	(175,888)
Total stockholders' equity	34,215	41,065
Total liabilities and stockholders' equity	$ 65,176	$ 67,611

Condensed Consolidated Balance Sheet (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Condensed Consolidated Balance Sheet
Accounts receivable, reserve for doubtful accounts	$ 50	$ 36
Accounts receivable, related parties	23	48
Accounts payable, related parties	0	36
Other accrued expenses, related parties	240	226
Deferred revenue, current, related parties	$ 29	$ 33
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, authorized shares	120,000,000	120,000,000
Common stock, shares issued	22,491,447	22,369,036
Common stock, shares outstanding	22,491,447	22,369,036

Condensed Consolidated Statement of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Total revenue	$ 12,337	$ 7,521
Cost of goods sold:
Total cost of goods sold and services	6,330	4,349
Gross profit	6,007	3,172
Operating expense:
Research and development (including stock compensation of $168 and $71 for the three months ended March 31, 2019 and 2018, respectively)	3,852	3,644
Selling, general and administrative (including stock compensation of $1,039 and $523 for the three months ended March 31, 2019 and 2018, respectively)	11,512	6,691
Total operating expenses	15,364	10,335
Loss from operations	(9,357)	(7,163)
Interest income (expense), net	21	(24)
Other (expense) income, net	(47)	(15)
Loss before income tax	(9,383)	(7,202)
Income tax provision	22
Net loss	$ (9,405)	$ (7,202)
Net loss per share attributable to common stockholders, basic and diluted	$ (0.42)	$ (0.33)
Weighted-average common shares outstanding, basic and diluted	22,422,960	21,788,605
Product revenue
Total revenue	$ 9,547	$ 4,745
Cost of goods sold:
Total cost of goods sold and services	4,248	2,773
Service and other revenue
Total revenue	2,790	2,507
Cost of goods sold:
Total cost of goods sold and services	$ 2,082	1,576
Collaboration and license revenue
Total revenue		$ 269

Condensed Consolidated Statement of Operations and Comprehensive Loss (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Cost of product revenue, related party activity	$ 35	$ 76
Stock compensation expense in cost of goods sold	17	10
Stock compensation expense in research and development expenses	168	71
Stock compensation expense in selling, general and administrative expenses	1,039	523
Product revenue
Related party revenue	80	93
Service and other revenue
Related party revenue	23	39
Stock compensation expense in cost of goods sold	60	32
Collaboration and license revenue
Related party revenue	$ 0	$ 269

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating activities
Net loss	$ (9,405)	$ (7,202)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization expense	409	272
Stock-based compensation expense	1,284	636
Non-cash interest expense	24	53
Changes in operating assets and liabilities:
Accounts receivable	(465)	1,148
Prepaid expenses and other assets	142	(923)
Inventory	(1,798)	(933)
Other non-current assets	3
Accounts payable	(1,321)	(677)
Accrued compensation and benefits, other accrued expenses and other current liabilities	(327)	(1,904)
Contract acquisition costs	(25)
Deferred revenue	45	(531)
Other non-current liabilities	6,082
Net cash used in operating activities	(5,352)	(10,061)
Investing activities
Purchases of property and equipment	(5,917)	(448)
Acquisitions, net of cash acquired		(3,001)
Net cash used in investing activities	(5,917)	(3,449)
Financing activities
Proceeds from sale of preferred stock, net of issuance costs		(53)
Proceeds from stock options exercised	503	84
Proceeds from ESPP purchase	328
Payments on notes payable		(972)
Net cash provided (used in) by financing activities	831	(941)
Net decrease in cash and cash equivalents	(10,438)	(14,451)
Cash, restricted cash, and cash equivalents at beginning of period	45,429	79,682
Cash, restricted cash, and cash equivalents at end of period	34,991	65,231
Supplemental cash flow information
Cash paid for interest	160	181
Purchases of property and equipment included in accounts payable	11
Reconciliation of cash, cash equivalents, and restricted cash:
Total cash, cash equivalents, and restricted cash	$ 45,429	$ 79,682

Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Common stock	Additional paid-in capital	Accumulated deficit	Total
Beginning Balance at Dec. 31, 2017	$ 22	$ 210,196	$ (144,352)	$ 65,866
Beginning balance (in shares) at Dec. 31, 2017	21,707,041
Increase (Decrease) in Stockholders' Equity
Exercise of common stock warrants (in shares)	16,718
Exercise of common stock options and vesting restricted stock		84		84
Exercise of common stock options and vesting restricted stock (in shares)	99,523
Common stock issuance offering costs		(53)		(53)
Stock-based compensation expense		636		636
Net loss			(7,202)	(7,202)
Ending Balance at Mar. 31, 2018	$ 22	210,863	(151,554)	59,331
Ending Balance (in shares) at Mar. 31, 2018	21,823,282
Beginning Balance at Dec. 31, 2018	$ 22	216,931	(175,888)	41,065
Beginning balance (in shares) at Dec. 31, 2018	22,369,036
Increase (Decrease) in Stockholders' Equity
Exercise of common stock options and vesting restricted stock	$ 1	502		503
Exercise of common stock options and vesting restricted stock (in shares)	102,361
ESPP stock purchase		328		328
ESPP stock purchase (in shares)	20,050
Stock-based compensation expense		1,284		1,284
Net loss			(9,405)	(9,405)
Ending Balance at Mar. 31, 2019	$ 23	$ 219,045	(184,853)	34,215
Ending Balance (in shares) at Mar. 31, 2019	22,491,447
Increase (Decrease) in Stockholders' Equity
Cumulative-effect adjustment for the adoption of ASC 606			$ 440	$ 440

Organization and operations	3 Months Ended
Organization and operations	Mar. 31, 2019
Organization and operations
Organization and operations	1. Organization and operations Quanterix Corporation (NASDAQ: QTRX) (the Company) is a life sciences company that has developed next generation, ultra-sensitive digital immunoassay platforms that advance precision health for life sciences research and diagnostics. The Company's platforms are based on our proprietary digital "Simoa" detection technology. The Company's Simoa bead-based and planar array platforms enable customers to reliably detect protein biomarkers in extremely low concentrations in blood, serum and other fluids that, in many cases, are undetectable using conventional, analog immunoassay technologies, and also allow researchers to define and validate the function of novel protein biomarkers that are only present in very low concentrations and have been discovered using technologies such as mass spectrometry. These capabilities provide the Company's customers with insight into the role of protein biomarkers in human health that has not been possible with other existing technologies and enable researchers to unlock unique insights into the continuum between health and disease. The Company is currently focusing on protein detection, but is also developing its bead-based technology to detect nucleic acids in biological samples. The Company currently markets the Simoa HD-1, a fully automated immunoassay bead-based platform with multiplexing and custom assay capability, and related assay test kits and consumable materials. The Company launched a second bead-based immunoassay platform (SR-X) in the fourth quarter of 2017 with a more compact footprint than the Simoa HD-1 Analyzer and less automation designed for lower volume requirements while still allowing multiplexing and custom assay capability. The Company initiated an early-access program for its third instrument (SP-X) on the new Simoa planar array platform in January 2019, with the full commercial launch commencing in April 2019. This compact instrument has the ability to reach a 10 plex and has custom assay capability. The Company also performs research services on behalf of customers to apply the Simoa technology to specific customer needs. The Company's primary customers are in the research use only market, which includes academic and governmental research institutions, the research and development laboratories of pharmaceutical manufacturers, contract research organizations, and specialty research laboratories. The Company acquired Aushon Biosystems, Inc. (Aushon) in January 2018. With the acquisition of Aushon, the Company acquired a CLIA certified laboratory, as well as Aushon's proprietary sensitive planar array detection technology. Leveraging its proprietary sophisticated Simoa image analysis and data analysis algorithms, the Company further refined this planar array technology to develop the SP-X instrument to provide the same Simoa sensitivity found in its bead-based platform. The Company believes that its existing unrestricted cash and cash equivalents of approximately $34.0 million at March 31, 2019 will be sufficient to allow the Company to fund its current operating plan through at least twelve months from the filing of the Company’s Quarterly Report on Form 10-Q for the quarterly period ended March 31, 2019. The Company may require additional financing in the future to fund working capital and pay its obligations as they come due. Additional financing might include issuance of equity securities, debt, cash from collaboration agreements or a combination of these. However, there can be no assurance that the Company will be successful in acquiring additional funding at levels sufficient to fund its operations or on terms favorable to the Company. Initial Public Offering In December 2017, the Company completed its initial public offering (IPO) in which the Company sold 4,916,480 shares of its common stock at the initial public offering price of $15.00 per share. The Company’s common stock began trading on The Nasdaq Global Market on December 7, 2017. The aggregate net proceeds received from the IPO, net of underwriting discounts and commissions and offering expenses, was $65.6 million. Immediately prior to the completion of the IPO, all then outstanding shares of convertible preferred stock were converted into 14,185,744 shares of common stock. The related carrying value of shares of preferred stock and warrants in the aggregate amount of $143.3 million was reclassified as common stock and additional paid‑in capital. Additionally, the Company filed an amended and restated certificate of incorporation with the Secretary of State of the State of Delaware, effective December 11, 2017 to, among other things, change the authorized number of shares of common stock to 120,000,000 and the authorized number of shares of preferred stock to 5,000,000. Basis of Presentation The interim condensed consolidated financial statements are unaudited. The unaudited condensed consolidated financial statements reflect, in the opinion of our management, all adjustments, consisting of only normal recurring adjustments, necessary for a fair presentation of financial position, results of operations, comprehensive loss and cash flows for each period presented in accordance with United States generally accepted accounting principles (U.S. GAAP) for interim financial information and with the instructions to Form 10‑Q and Article 10 of Regulation S-X. Accordingly, certain information and disclosures normally included in financial statements prepared in accordance with U.S. GAAP have been condensed or omitted. These interim condensed consolidated financial statements should be read in conjunction with the audited consolidated financial statements and related notes thereto included in our Annual Report on Form 10‑K for the year ended December 31, 2018 filed with the Securities and Exchange Commission on March 18, 2019 (the 2018 Annual Report on Form 10-K). The consolidated financial information as of December 31, 2018 has been derived from the audited 2018 consolidated financial statements included in our 2018 Annual Report on Form 10‑K. Reverse Stock Split On December 4, 2017, the Company effected a reverse stock split of its common stock at a ratio of 1‑for‑3.214. The shares of common stock subject to then outstanding stock options were adjusted accordingly to reflect the reverse stock split. All common stock and related per share amounts presented in these financial statements and related notes have been retroactively adjusted to reflect the 1‑for‑3.214 reverse stock split.

Significant accounting policies

3 Months Ended

Mar. 31, 2019

Significant accounting policies

Significant accounting policies

2. Significant accounting policies

Principles of consolidation

The condensed consolidated financial statements have been prepared in accordance with U.S. GAAP and include the accounts of Quanterix Corporation and its wholly‑owned subsidiaries. All material intercompany transactions and balances have been eliminated in consolidation.

Use of estimates

The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. In making those estimates and assumptions, the Company bases its estimates on historical experience and on various other assumptions believed to be reasonable. The Company’s significant estimates included in the preparation of the consolidated financial statements are related to revenue recognition, fair value of equity instruments and notes receivable, fair value of assets acquired and liabilities assumed in acquisitions, valuation allowances recorded against deferred tax assets, and stock‑based compensation. Actual results could differ from those estimates.

Business combinations

Under the acquisition method of accounting, the Company allocates the fair value of the total consideration transferred to the tangible and identifiable intangible assets acquired and liabilities assumed based on their estimated fair values on the date of acquisition. The fair values assigned, defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between willing market participants, are based on estimates and assumptions determined by management. The excess consideration over the aggregate fair value of tangible and intangible assets, net of liabilities assumed, is recorded as goodwill. These valuations require significant estimates and assumptions, especially with respect to intangible assets.

The Company typically uses the discounted cash flow method to value acquired intangible assets. This method requires significant management judgment to forecast future operating results and establish residual growth rates and discount factors. The estimates used to value and amortize intangible assets are consistent with the plans and estimates that are used to manage the business and are based on available historical information and industry estimates and averages. If the subsequent actual results and updated projections of the underlying business activity change compared with the assumptions and projections used to develop these values, the Company could experience impairment charges. In addition, the Company has estimated the economic lives of certain acquired assets and these lives are used to calculate depreciation and amortization expense. If estimates of the economic lives change, depreciation or amortization expenses could be accelerated or slowed.

Restricted Cash

Restricted cash primarily represents collateral for a letter of credit issued as security for the lease for the Company’s new headquarters. The restricted cash is long term in nature as the Company will not have access to the funds until more than one year from March 31, 2019.

Recent accounting pronouncements

The Company is considered to be an “emerging growth company” as defined in the Jumpstart Our Business Startups Act of 2012, as amended (JOBS Act). The JOBS Act provides that an emerging growth company can take advantage of an extended transition period for complying with new or revised accounting standards. Thus, an emerging growth company can delay the adoption of certain accounting standards until those standards would otherwise apply to private companies. The Company has elected to avail itself of this extended transition period and, as a result, the Company will not be required to adopt new or revised accounting standards on the relevant dates on which adoption of such standards is required for other public companies so long as the Company remains an emerging growth company.

On January 1, 2019, the Company adopted Accounting Standards Codification (ASC) Topic 606, Revenue from Contracts with Customers (ASC 606), using the modified retrospective method. Under ASC 606, revenue is recognized upon the transfer of control of goods or services to customers and reflects the amount of consideration to which an entity expects to be entitled in exchange for those goods or services. The adoption of ASC 606 has been applied to customer contracts that were not completed as of January 1, 2019, and did not materially change the pattern of revenue recognition for its current customer contracts. The Company's consolidated financial statements for the prior-year period have not been revised and are reflective of the revenue recognition requirements which were in effect for that period.

The Company recorded a decrease to the accumulated deficit of $0.4 million as of January 1, 2019 for the cumulative effect primarily related to the deferral of sales commissions .

In accordance with the reporting requirements of ASC 606, the disclosure of the impact on the Company's consolidated balance sheet and statement of operations, as a result of adopting the provisions of ASC 606, was as follows (in thousands):


											Prior to
	As										adoption of
	reported				Adjusted under		As reported				ASC 606
	December				ASC 606		March 31,				March 31,
	31, 2018		Adjustments		January 1, 2019		2019		Adjustments		2018
Assets:
Accounts receivable	$	6,792	$	47	$	6,839	$	7,303	$	(47)	$	7,256
Prepaid expenses and other current assets		2,330		288		2,618		2,502		26		2,528
Other non-current assets		536		19		555		550		(1)		549

Liabilities:
Deferred revenue		5,437		43		5,480		5,484		27		5,511
Deferred revenue, net of current portion		520		43		563		431		(2)		429

Stockholders’ equity:
Accumulated deficit	$	(175,888)	$	(440)	$	(176,328)	$	(184,853)	$	(47)	$	(184,900)


	For the three months ended March 31, 2019
					Under ASC
	Under ASC 606		Adjustment		605
Product revenue	$	9,547	$	(33)	$	9,514
Service revenue		2,790		105		2,895
COGS		2,082		1		6,331
Gross profit		6,007		71		6,078
Selling general and administrative expenses		11,512		24		11,536
Net loss	$	(9,405)	$	47	$	(9,358)

The adoption of ASC 606 is discussed in further detail in Note 3.

The Company adopted accounting standards update (ASU) 2016-1, which requires equity investments (except those accounted for under the equity method of accounting or those that result in consolidation of the investee) to be measured at fair value with changes in fair value recognized in net income. For equity investments without readily determinable fair values that do not qualify for the practical expedient to estimate fair value using the net asset value per share or its equivalent, the Company has elected to measure these investments at cost minus impairment, if any, plus or minus changes resulting from observable price changes in orderly transactions for the identical or similar investment of the same issuer. This election is made for each investment separately and is reassessed at each reporting period as to whether the investment continues to qualify for this election. Additionally, at each reporting period, the Company makes a qualitative assessment considering impairment indicators to evaluate whether the investment is impaired. The adoption of this standard did not have a material effect.

In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842): Recognition and Measurement of Financial Assets and Financial Liabilities (ASU 2016-02). Under ASU 2016-02, lessees will be required to recognize a lease liability and a right-of-use asset for all leases (with the exception of short term leases) at the commencement date. Lessor accounting under ASU 2016-02 is largely unchanged. ASU 2016-02 is effective for the Company for the year ending December 31, 2020. Early adoption is permitted. Under ASU 2016-02, lessees (for capital and operating leases) and lessors (for sales-type, direct financing and operating leases) must apply a modified retrospective transition approach for leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements. Lessees and lessors may not apply a full retrospective transition approach. The Company is currently evaluating the expected impact of ASU 2016-2 on its financial statements.

In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments — Credit Losses: Measurement of Credit Losses on Financial Instruments (ASU 2016-13), which amends the impairment model by requiring entities to use a forward-looking approach based on expected losses to estimate credit losses on certain types of financial instruments, including trade receivables and available-for-sale debt securities. The standard is effective for the Company beginning in the first quarter of 2020, with early adoption permitted. The Company is currently evaluating the expected impact of ASU 2016-13 on its financial statements.

In January 2017, the FASB issued ASU No. 2017-04, Intangibles - Goodwill and Other (Topic 350) - Simplifying the Test for Goodwill Impairment. This ASU eliminates Step 2 from the goodwill impairment test. In addition, income tax effects from any tax deductible goodwill on the carrying amount of the reporting unit should be considered when measuring the goodwill impairment loss, if applicable. The amendments also eliminate the requirements for any reporting unit with a zero or negative carrying amount to perform a qualitative assessment and, if it fails that qualitative test, to perform Step 2 of the goodwill impairment test. An entity still has the option to perform the qualitative assessment for a reporting unit to determine if the quantitative impairment test is necessary. This ASU is effective for annual periods beginning after December 15, 2019 and interim periods within those annual periods. Early adoption is permitted, for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. The Company does not expect adoption of this ASU to be material to its financial statements.

In August 2018, the FASB issued ASU No. 2018-13, Fair Value Measurement (Topic 820), Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement. This ASU removed the following disclosure requirements: (1) the amount of and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy; (2) the policy for timing of transfers between levels; and (3) the valuation processes for Level 3 fair value measurements. Additionally, this update added the following disclosure requirements: (1) the changes in unrealized gains and losses for the period included in other comprehensive income for recurring Level 3 fair value measurements held at the end of the reporting period; (2) the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements. For certain unobservable inputs, an entity may disclose other quantitative information (such as the median or arithmetic average) in lieu of the weighted average if the entity determines that other quantitative information would be a more reasonable and rational method to reflect the distribution of unobservable inputs used to develop Level 3 fair value measurements. ASU No. 2018-13 will be effective for fiscal years beginning after December 15, 2019 with early adoption permitted. As of March 31, 2019, the Company has not elected to early adopt this guidance but does not expect that the adoption of this guidance will have a material effect on its consolidated financial statements.

There have been no other material changes to the significant accounting policies and recent accounting pronouncements previously disclosed in the 2018 Annual Report on Form 10‑K.

Revenue recognition

3 Months Ended

Mar. 31, 2019

Revenue recognition

Revenue recognition

3. Revenue recognition

The Company recognizes revenue when a customer obtains control of a promised good or service. The amount of revenue recognized reflects consideration that the Company expects to be entitled to receive in exchange for these goods and services, incentives and taxes collected from customers, that are subsequently remitted to governmental authorities.

The Company adopted ASC 606 on January 1, 2019, using the modified retrospective method for all contracts not completed as of the date of adoption. The reported results for 2019 reflect the application of ASC 606 guidance, while the reported results for 2018 were prepared under ASC 605, Revenue Recognition.

Customers

The Company’s customers primarily consist of entities engaged in the life sciences research market that pursue the discovery and development of new drugs for a variety of neurologic, cardiovascular, oncologic and other protein biomarkers associated with diseases. The Company’s customer base exceeds 200 customers and includes several of the largest biopharmaceutical companies, academic research organizations and distributors who serve certain geographic markets.

Product Revenue

The Company’s products are composed of analyzer instruments, assay kits and other consumables such as reagents. Products are sold directly to biopharmaceutical and academic research organizations or are sold through distributors in EMEA and Asia Pacific regions. The sales of instruments are generally accompanied by an initial year of implied service-type warranties, and may be bundled with assays and other consumables and may also include other items such as training and installation of the instrument and/or an extended service warranty. Revenues from the sale of products are recognized at a point in time when the Company transfers control of the product to the customer, which is upon installation for instruments sold to direct customers, and based upon shipping terms for assay kits and other consumables. Revenue for instruments sold to distributors is generally recognized based upon shipping terms (either upon shipment or delivery).

Service and Other Revenue

Service revenues are composed of contract research services, initial implied one-year service-type warranties, extended services contracts and other services such as training. Contract research services are provided through the Company’s Accelerator Laboratory and generally consist of fixed fee contracts. Revenues from contract research services are recognized at a point in time when the Company completes and delivers its research report on each individually completed study, or over time if the contractual provisions allow for the collection of transaction consideration for costs incurred plus a reasonable margin through the period of performance of the services. Revenues from service-type warranties are recognized ratably over the contract service period. Revenues from other services are immaterial.

Collaboration and License Revenue

The Company may enter into agreements to license the intellectual property and know-how associated with its instruments in exchange for license fees and future royalties (as described below). The license agreements provide the licensee with a right to use the intellectual property with the license fee revenues recognized at a point in time as the underlying license is considered functional intellectual property. The Company has not recognized any revenues from royalties.

Payment terms

The Company’s payment terms vary by the type and location of customer and the products or services offered. Payment from customers is generally required in a term ranging from 30 to 45 days from date of shipment or satisfaction of the performance obligation with no discounts for early payment. The Company does not provide extended payment terms or financing arrangements to its customers.

Disaggregated Revenue

When disaggregating revenue, the Company considered all of the economic factors that may affect its revenues. The following tables disaggregate the Company's revenue from contracts with customers by revenue type:


	Three Months Ended March 31, 2019
($in thousands)	NA		EMEA		Asia Pacific		Total
Product revenues
Instruments	$	1,397	$	1,145	$	874	$	3,416
Consumable and other products	$	3,619	$	2,088	$	424	$	6,131
Totals	$	5,016	$	3,233	$	1,298	$	9,547

Service and other revenues
Service-type warranties	$	689	$	234	$	37	$	960
Research services	$	1,504	$	—	$	—	$	1,504
Other services	$	201	$	108	$	17	$	326
Totals	$	2,394	$	342	$	54	$	2,790

The Company’s contracts with customers may include promises to transfer multiple products and services to a customer. The Company will combine any performance obligations that are immaterial with one or more other performance obligations that are material to the contract For arrangements with multiple performance obligations, the Company allocates the contract transaction price, including discounts, to each performance obligation based on its relative standalone selling price. Judgment is required to determine the standalone selling price for each distinct performance obligation. The Company determines standalone selling prices based on prices charged to customers in observable transactions, and uses a range of amounts to estimate standalone selling prices for each performance obligation. The Company may have more than one range of standalone selling price for certain products and services based on the pricing for different customer classes.

Variable consideration in the Company’s contracts primarily relates to (i) sales- and usage-based royalties related to the license of intellectual property in collaboration and license contracts and (ii) certain non-fixed fee research services contracts. ASC 606 provides for an exception to estimating the variable consideration for sales- and usage-based royalties related to the license of intellectual property, such that the sales- or usage-based royalty will be recognized in the period the underlying transaction occurs. The Company has not recorded any sales- or usage-based royalty revenue for the three months ended March 31, 2019.

The aggregate amount of transaction price that is allocated to performance obligations that have not yet been satisfied or are partially satisfied as of March 31, 2019 is $5.9 million. This amount principally consists of $3.6 million billed for undelivered services related to initial and extended service-type warranties and research services, as well as $1.7 million related to undelivered licenses of intellectual property for a diagnostics company (see Note 12 below). Of these amounts, $2.6 million is expected to be recognized as revenue in the next 12 months, with the remainder to be recognized within the 24 months thereafter.

Changes in deferred revenue from contracts with customers were as follows (in thousands):


	Three Months
	Ended March 31,
	2019
Balance at December 31, 2018	$	5,957
606 adoption adjustment		(86)
Deferral of revenue		1,004
Recognition of deferred revenue		(960)
Balance at March 31, 2019	$	5,915

Costs to Obtain a Contract

The Company’s sales commissions are generally based on revenues of the Company. The Company has determined that certain commissions paid under its sales incentive programs meet the requirements to be capitalized as they are incremental and would not have occurred absent a customer contract. The change in the balance of costs to obtain a contract are as follows (in thousands):


	Three Months
	Ended March 31,
	2019
Balance at December 31, 2018	$	—
606 adoption adjustment		307
Deferral of costs to obtain a contract		194
Recognition of costs to obtain a contract		(170)
Balance at March 31, 2019	$	331

The Company has classified the balance of capitalized costs to obtain a contract as a component of prepaid expenses and other current assets as of January 1, 2019 and March 31, 2019 and classifies the expense as a component of cost of goods sold and selling, general and administrative expense over the estimated life of the contract.. The Company considers potential impairment in these amounts each period.

ASC 606 provides entities with certain practical expedients and accounting policy elections to minimize the cost and burden of adoption.

The Company does not disclose the value of unsatisfied performance obligations for (i) contracts with original expected length of one year or less and (ii) contracts for which revenue is recognized at the amount to which the Company has the right to invoice for services performed.

The Company will exclude from its transaction price any amounts collected from customers related to sales and other similar taxes.

When determining the transaction price of a contract, an adjustment is made if payment from a customer occurs either significantly before or significantly after performance, resulting in a significant financing component. The Company does not assess whether a significant financing component exists if the period between when the Company performs its obligations under the contract and when the customer pays is one year or less. None of the Company’s contracts contained a significant financing component as of January 1, 2019 or March 31, 2019

The Company has elected to account for the shipping and handling as an activity to fulfill the promise to transfer the product, and therefore will not evaluate whether shipping and handling activities are promised services to its customers.

Net loss per share

3 Months Ended

Mar. 31, 2019

Net loss per share

Net loss per share

4. Net loss per share

Basic net loss per common share attributable to common stockholders is calculated by dividing the net loss attributable to common stockholders by the weighted‑average number of common shares outstanding during the period, without consideration for potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss attributable to common stockholders by the weighted‑average number of common shares and potentially dilutive securities outstanding for the period determined using the treasury‑stock and if‑converted methods. For purposes of the diluted net loss per share calculation, preferred stock, unvested restricted common stock and stock options are considered to be potentially dilutive securities, but are excluded from the calculation of diluted net loss per share because their effect would be anti‑dilutive and therefore basic and diluted net loss per share were the same for all periods presented.

The following table sets forth the outstanding potentially dilutive securities that have been excluded in the calculation of diluted net loss per share because to do so would be anti‑dilutive (in common stock equivalent shares):


	March 31,
	2019	2018
Unvested restricted common stock and restricted stock units	419,716	153,428
Outstanding stock options	2,802,343	2,450,846
Outstanding warrants	76,041	76,041
Total	3,298,100	2,680,315

As of March 31, 2019 and 2018, the Company had an obligation to issue warrants to purchase an additional 93,341 shares of common stock to a vendor if a contract is terminated prior to a minimum purchase commitment being met. No amounts are presented in the table above for this obligation to issue a warrant as the issuance of the warrant is not considered probable.

Fair value of financial instruments

3 Months Ended

Mar. 31, 2019

Fair value of financial instruments

Fair value of financial instruments

5. Fair value of financial instruments

ASC Topic 820, Fair Value Measurement (ASC 820), establishes a fair value hierarchy for instruments measured at fair value that distinguishes between assumptions based on market data (observable inputs) and the Company’s own assumptions (unobservable inputs). Observable inputs are inputs that market participants would use in pricing the asset or liability based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company’s assumptions about the inputs that market participants would use in pricing the asset or liability, and are developed based on the best information available in the circumstances.

ASC 820 identifies fair value as the exchange price, or exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As a basis for considering market participant assumptions in fair value measurements, ASC 820 establishes a three‑tier fair value hierarchy that distinguishes between the following:

Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities;

Level 2 inputs are inputs other than quoted prices that are observable for the asset or liability, either directly or indirectly; and

Level 3 inputs are unobservable inputs that reflect the Company’s own assumptions about the assumptions market participants would use in pricing the asset or liability.

Fair value measurements as of March 31, 2019 are as follows (in thousands):


			Quoted prices
			in active		Significant other		Significant
			markets		observable		unobservable inputs
Description	Total		(Level 1)		inputs (Level 2)		(Level 3)
Financial assets
Cash equivalents	$	31,958	$	31,958	$	—	$	—
Note receivable		150		—		—		150
	$	32,108	$	31,958	$	—	$	150

Fair value measurements as of December 31, 2018 are as follows (in thousands):


			Quoted prices		Significant other		Significant
			in active		observable		Significant
			markets		inputs (Level 2)		unobservable inputs
Description	Total		(Level 1)		(Level 2)		(Level 3)
Financial assets
Cash equivalents	$	42,608	$	42,608	$	—	$	—
Note receivable		150		—		—		150
	$	42,758	$	42,608	$	—	$	150

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Inventory

3 Months Ended

Mar. 31, 2019

Inventory

Inventory

6. Inventory

Inventory consists of the following (in thousands):


	March 31,		December 31,
	2019		2018
Raw Materials	$	2,999	$	1,546
Work in process		2,662		2,331
Finished goods		2,081		2,068
Total	$	7,742	$	5,945

Inventory comprises commercial instruments, assays, and the materials required to manufacture assays.

Investments	3 Months Ended
Investments	Mar. 31, 2019
Investments
Investments	7. Investments During the third quarter of 2016, the Company purchased a minority interest in preferred stock in a privately held company for $0.3 million. During the third quarter of 2018, the Company was issued a convertible note by a privately held company having a principal amount of $0.2 million. The preferred stock investment is recorded on a cost basis in other non-current assets on the accompanying balance sheets as the Company does not have a controlling interest, does not have the ability to exercise significant influence over the privately held companies, and the fair value of these equity investment is not readily determinable. The Company performs an impairment analysis at each reporting period to determine if there is any readily available fair value information that would indicate an impairment. The Company has determined there was no impairment during the three months ended March 31, 2019 or in any prior period. The convertible note is held as an available-for-sale investment, which is carried at fair market value, with the unrealized gains and losses included in the determination of comprehensive income and reporting stockholders equity. When determining the estimated fair value of the convertible notes, the Company used a commonly accepted valuation methodology and market-based risk measurement that are indirectly observable, such as credit risk.

Other accrued expenses

3 Months Ended

Mar. 31, 2019

Other accrued expenses

Other accrued expenses

8. Other accrued expenses

Other accrued expenses consist of the following (in thousands):


	March 31,		December 31,
	2019		2018
Accrued inventory	$	795	$	599
Accrued royalties		399		323
Accrued professional services		851		723
Accrued development costs		1,067		795
Accrued other		662		689
Total accrued expenses	$	3,774	$	3,129

Warrants, stock-based compensation, stock options, restricted stock and restricted stock units

3 Months Ended

Mar. 31, 2019

Warrants, stock-based compensation, stock options, restricted stock and restricted stock units

Warrants, stock-based compensation, stock options, restricted stock and restricted stock units

9. Warrants, stock-based compensation, stock options, restricted stock and restricted stock units

Warrants

The Company issued no warrants during the three months ended March 31, 2019 and had 76,041 warrants outstanding as of March 31, 2019.

Stock-based compensation

Share‑based compensation expense for all stock awards consists of the following (in thousands):


	Three months ended March 31,
	2019		2018
Cost of product revenue	$	17	$	10
Cost of service and other revenue		60		32
Research and development		168		71
General and administrative		1,039		523
Total	$	1,284	$	636

As of March 31, 2019, under the 2007 Stock Option and Grant Plan (the 2007 Plan), options to purchase 1,691,565 shares of common stock were outstanding, 1,103,535 shares of common stock had been issued and were outstanding pursuant to the exercise of options, no shares of common stock had been issued and were outstanding pursuant to restricted or unrestricted stock awards, and no shares of common stock were available for future awards. In connection with the completion of the IPO, the Company terminated the 2007 Plan.

In December 2017, the Company adopted the 2017 Employee, Director and Consultant Equity Incentive Plan (the 2017 Plan), under which it may grant incentive stock options, non‑qualified stock options, restricted stock, and other stock‑based awards. As of December 31, 2017, the 2017 Plan allowed for the issuance of up to 1,042,314 shares or options to purchase shares of common stock plus up to 2,490,290 shares of common stock represented by awards granted under the 2007 Plan that are forfeited, expire or are cancelled without delivery of shares or which result in the forfeiture of shares of common stock back to the Company on or after the date the 2017 Plan becomes effective. The 2017 Plan contains an “evergreen” provision, which allows for an annual increase in the number of shares of common stock available for issuance under the 2017 Plan on the first day of each fiscal year during the period beginning in fiscal year 2019 and ending in fiscal year 2027. The annual increase in the number of shares shall be equal to the lowest of: 4% of the number of shares of common stock outstanding as of such date; and an amount determined by the Company’s Board of Directors or Compensation Committee. The number of shares available for grant under the 2017 Plan increased by 894,761 on January 1, 2019 due to this provision. As of March 31, 2019, 1,373,307 shares were available for grant under the 2017 Plan.

In December 2017, the Company adopted the 2017 Employee Stock Purchase Plan (the 2017 ESPP). The 2017 ESPP contains an “evergreen” provision, which allows for an increase on the first day of each fiscal year beginning with fiscal year 2018. The increase in the number of shares shall be equal to the lowest of: 1% of the number of shares of common stock outstanding on the last day of the immediately preceding fiscal year or an amount determined by the Company’s Board of Directors or Compensation Committee. The number of shares available for grant under the 2017 ESPP increased by 223,690 on January 1, 2019 due to this provision. As of March 31, 2019, the 2017 ESPP allowed for the issuance of up to 649,233 shares of common stock and 629,173 shares were available for grant under the 2017 ESPP.

Stock options

Under the 2007 Plan and the 2017 Plan, stock options may not be granted with exercise prices of less than fair market value on the date of the grant. Options generally vest ratably over a four‑year period with 25% vesting on the first anniversary and the remaining 75% vesting ratably on a monthly basis over the remaining three years. These options expire ten years after the grant date. Activity under the 2007 Plan and the 2017 Plan was as follows:


		Weighted-average		Remaining contractual	Aggregate intrinsic value
	Options	exercise price		life (in years)	(in thousands)
Outstanding at December 31, 2018	2,476,911	$	9.65	7.73		22,108
Granted	460,674	$	21.32
Exercised	(78,712)	$	6.38
Cancelled	(56,530)	$	13.78
Outstanding at March 31, 2019	2,802,343	$	11.57	7.90		39,954
Vested and expected to vest at March 31, 2019	2,802,343	$	11.57	7.90		39,954
Exercisable at March 31, 2019	1,233,379	$	6.69	6.55		23,608

Using the Black-Scholes option pricing model, the weighted-average fair value of options granted to employees and directors during the three months ended March 31, 2019 and 2018 was $7.90 and $8.72 per share, respectively. The expense related to awards granted to employees was $0.7 million for the three months ended March 31, 2019 and 2018. The intrinsic value of stock options exercised was $1.2 million and $1.0 million for the three months ended March 31, 2019 and 2018, respectively. Activity related to non-employee awards was not material to the three months ended March 31, 2019 and 2018.

Restricted stock

Restricted common stock awards represent shares of common stock issued to employees subject to forfeiture if the vesting conditions are not satisfied. In December 2014, the Company issued 78,912 shares of restricted common stock to a director of the Company under the 2007 Plan. Under the terms of the agreement, shares of common stock issued are subject to a four year vesting schedule. Vesting occurs periodically at specified time intervals and specified percentages. In January 2015, the Company issued 781,060 shares of restricted common stock to an executive of the Company under the 2007 Plan. The majority of these shares were issued subject to a four year vesting schedule with 25% vesting on the first anniversary and the remaining vesting 75% ratably on a monthly basis over the remaining three years, while another portion was issued subject to performance based vesting. The vesting of performance based awards is dependent upon achievement of specified financial targets of the Company. The majority of the performance criteria were achieved during the years ended December 31, 2016 and 2015 and the remaining unvested awards with performance conditions are not material. No restricted stock awards were granted or vested during the three months ended March 31, 2019.

Restricted stock units

Restricted stock units (RSUs) represent the right to receive shares of common stock upon meeting specified vesting requirements. In the three months ended March 31, 2019, the Company issued 130,085 RSUs to employees of the Company under the 2017 Plan. Under the terms of the agreements, 82,463 of the RSUs issued are subject to a four year vesting schedule with 25% vesting on the first anniversary and the remaining vesting 75% ratably on a monthly basis over the remaining three years; 15,890 of the RSUs vest on December 31, 2019; and for 31,731 of the RSUs, 1,983 vest on March 31, 2019 with the remaining vesting evenly over 45 months thereafter. A summary of restricted stock unit activity is as follows:


		Weighted-average
		grant date
		fair value
	Shares	per share
Unvested RSUs as of December 31, 2018	321,662	$	15.84
Granted	130,085	$	21.37
Vested	(23,649)	$	16.36
Cancelled	(8,382)	$	18.88
Unvested RSUs as of March 31, 2019	419,716	$	17.46

The expense related to awards granted to employees and directors was $0.5 million and $0.2 for the three months ended March 31, 2019 and 2018, respectively.

At March 31, 2019, there was $7.0 million of total unrecognized compensation cost related to unvested restricted stock, which is expected to be recognized over the remaining weighted‑average vesting period of 3.02 years.

Commitments and contingencies

3 Months Ended

Mar. 31, 2019

Commitments and contingencies

Commitments and contingencies

10. Commitments and contingencies

Tufts University

In June 2007, the Company entered into a license agreement (the License Agreement) for certain intellectual property with Tufts University (Tufts). Tufts is a related party to the Company due to Tufts’ equity ownership in the Company and because a board member of the Company’s Board of Directors was affiliated with Tufts. The License Agreement, which was subsequently amended, is exclusive and sub licensable, and will continue in effect on a country by country basis as long as there is a valid claim of a licensed patent in a country. The Company is committed to pay license and maintenance fees, prior to commercialization, in addition to low single digit royalties on direct sales and services and a royalty on sublicense income. During the three months ended March 31, 2019 and 2018, the Company recorded royalty expense of $0.2 million and $0.1 million, respectively, in cost of product revenue on the consolidated statements of operations and comprehensive loss.

During the year ended December 31, 2012, the Company entered into a license agreement for certain intellectual property with a third party. The non‑exclusive, non‑sublicensable third party’s license provides the Company access to certain patents specifically for protein detection, and shall be in effect until the expiration of the last licensed patent. In consideration for these rights, the Company committed to certain license fees, milestone payments, minimum annual royalties and a mid‑single digit royalty. The Company is required to make mid‑single digit royalty payments on net sales of products and services which utilize the licensed technology. The Company must pay the greater of calculated royalties on net sales or an annual minimum royalty of $50,000. During each of the three months ended March 31, 2019 and 2018, the Company recorded royalty expense of less than $0.1 million in cost of product revenue on the consolidated statements of operations.

Lease commitments

During the year ended December 31, 2014, the Company entered into a lease agreement for the Company's current corporate headquarters in Lexington, Massachusetts with a lease term that expires in June 2020; however, in November 2018, the Company agreed to terminate the lease with the lessor effective May 31, 2019. The lease was terminated in connection with the Company signing a new lease in Billerica, Massachusetts. On October 2, 2018, the Company entered into a 137 month operating lease for the Company's new headquarters in Billerica, Massachusetts. The lease contains a period of free rent and escalating monthly rent payments. As part of the lease, the Company was required to enter into a $1.0 million Letter of Credit drawable by the lessor under specifically outlined conditions. The amount of the Letter of Credit will be reduced at 41 and 65 months after the commencement date of the lease to $750,000 and then $250,000, respectively. The $1.0 million Letter of Credit is recorded as restricted cash on the balance sheet.

In connection with the acquisition of Aushon in January 2018, the Company assumed the existing Aushon lease for facilities in Billerica, Massachusetts. In August 2018 the Company terminated the Aushon lease effective September 1, 2019. The Company is required to pay a termination fee no later than July 1, 2019 in consideration for the early termination.

Rent expense is recognized straight‑line over the course of the lease term. As of March 31, 2019, $6.3 million of deferred rent expense was recorded in other non‑current liabilities, and less than $0.1 million was recorded in other accrued expenses. The table below includes committed lease expenditures related to the new lease.

As of March 31, 2019, the minimum future rent payments under the lease agreements are as follows (in thousands):


2019	$	831
2020		2,013
2021		3,290
2022		3,372
2023 and Forward		29,207
	$	38,713

The Company recorded $1.0 million and $0.3 million in rent expense for the three months ended March 31, 2019 and 2018, respectively.

Development and supply agreement

Through the Company’s development agreement with STRATEC Biomedical, as amended in December 2016, the parties agreed on additional development services for an additional fee, which is payable when the additional development is completed. A total of $1.5 million is payable to STRATEC upon completion of the development activities. This amount is being recorded to research and development expense and accrued expenses as the services are performed. The services were completed during the year ending December 31, 2018. Substantive efforts related to these additional development activities started in the first quarter of 2019 and are expected to continue through the second quarter of 2019.

The Company’s supply agreement with STRATEC Biomedical requires the Company to purchase a minimum number of commercial units over a seven‑year period ending in May 2021. If the Company were to fail to purchase a required number of commercial units, the Company would be obligated to pay termination costs plus a fee based on the shortfall of commercial units purchased compared to the required minimum amount. Based on the number of commercial instruments purchased as of March 31, 2019, assuming no additional commercial units were purchased, this fee would equal $10.9 million. The amount the Company could be obligated to pay under the minimum purchase commitment is reduced as each commercial unit is purchased. Also, if the Company terminates the supply agreement under certain circumstances and has not purchased a required number of commercial units, it would be obligated to issue warrants to purchase 93,341 shares of common stock (the Supply Warrants) at $0.003214 per share. The Company believes that it will purchase sufficient units to meet the requirements of the minimum purchase commitment and, therefore, has not accrued for any of the potential cash consideration. The Supply Warrants are accounted for at fair value; however, the fair value of the Supply Warrants as of March 31, 2019 and December 31, 2018 was insignificant as there was a low probability of the warrants being issued.

Legal contingencies

The Company is subject to claims in the ordinary course of business; however, the Company is not currently a party to any pending or threatened litigation, the outcome of which would be expected to have a material adverse effect on its financial condition or the results of its operations. The Company accrues for contingent liabilities to the extent that the liability is probable and estimable.

Notes payable

3 Months Ended

Mar. 31, 2019

Notes payable

Notes payable

11. Notes payable

Loan agreement

On April 14, 2014, the Company executed a Loan Agreement with a lender, as subsequently amended in March 2015, January 2016, March 2017, July 2017, August 2018, October 2018, and April 2019. As of March 31, 2019, there were no additional amounts available to borrow under the debt facility. The interest rate on this term loan is variable based on a calculation of the prime rate less 5.25% with a minimum interest rate of 8.25%. Interest is paid monthly beginning the month following the borrowing date. At loan inception and in connection with the amendments, the Company issued the lender warrants to purchase shares of stock. The Loan Agreement also contains prepayment penalties and an end of term charge. Fees incurred upon execution of the agreements, and the fair value of warrants on the date of grant were accounted for as a reduction in the book value of debt and accreted through interest expense, using the effective interest rate method, over the term of the debt.

No end of term charges or principal payments were paid during the three months ended March 31, 2019. Under the terms of the amendment in April 2019, principal payments were delayed until 2021 (Note 16). Under the amended Loan Agreement, the remaining outstanding principal will be paid upon maturity of the note in 2021 (Note 16). As of March 31, 2019, the remaining loan balance is classified as a long term liability since all principal payments are due greater than twelve months after the balance sheet date.

As of March 31, 2019, debt payment obligations due based on principal payments are as follows (in thousands):


2019	$	—
2020		—
2021		7,763
	$	7,763

Non‑cash interest expense related to debt discount amortization and accretion of end of term fees was less than $0.1 million and $0.1 million for the three months ended March 31, 2019 and 2018, respectively.

The Company added $5.3 million of leasehold improvements related to the new lease.

Collaboration and license arrangements	3 Months Ended
Collaboration and license arrangements	Mar. 31, 2019
Collaboration and license arrangements
Collaboration and license arrangements	12. Collaboration and license arrangements Joint development and license agreement The JDLA with bioMérieux, a related party, was amended in 2016 (the JDLA). Following the amendment, a total of $3.2 million of consideration was assigned to the deliverables and collaboration activities outlined in the Amended JDLA. The consideration of $3.2 million will be recognized over the performance period which began in the fourth quarter 2016. On September 6, 2018, bioMérieux notified the Company that it was terminating the Amended JDLA, forfeiting any future IVD licensing rights to the Company’s Simoa technology and enabling the Company to consolidate and regain control of all Simoa IVD licensing and IP rights. As a result of the termination, the Company immediately recognized $1.6 million in deferred revenue related to the agreement. Evaluation and option agreements and license agreement In 2015, the Company entered into three agreements, for three separate fields, with a diagnostic company for the evaluation of the Company’s Simoa technology. These agreements each allowed for the option to negotiate a license agreement. In return, the Company received non‑refundable payments totaling $2.0 million. In December 2016, the diagnostic company exercised one of its options and the parties entered into a non-exclusive license agreement in one of the fields. This agreement has a one‑time non‑refundable license fee of $1.0 million and the right to receive running low single digit royalties on licensed products. The negotiation periods for the other two agreements were extended and the negotiations remain ongoing. Upon execution of the license in one of the fields in December 2016, the $1.0 million license fee, in addition to the $0.8 million allocated to the option for this field, resulted in a total of $1.8 million of consideration being recognized as revenue as there were no remaining undelivered performance obligations. In December 2018, the Company entered into an option agreement for the rights to negotiate an exclusive license in this field with the diagnostic company. In exchange for the rights to negotiate an exclusive agreement, the Company will receive $0.5 million in consideration. As the right to negotiate with the Company has not been executed, the consideration from this agreement is deferred until the sooner of the execution of the contract or the end of the option period. Because the negotiations remain ongoing with respect to the other two fields and the options have not been exercised, the consideration allocated to these options of $1.7 million has been deferred and is recorded as deferred revenue as of March 31, 2019 and December 31, 2018.

Employee benefit plans	3 Months Ended
Employee benefit plans	Mar. 31, 2019
Employee benefit plans
Employee benefit plans	13. Employee benefit plans The Company sponsors a 401(k) savings plan for its employees The Company may make discretionary contributions for each 401(k) plan year. During the three months ended March 31, 2019, the Company made contributions of $0.1 million and during the three months ended March 31, 2018, the Company did not make any contribution.

Goodwill and Acquired Intangible Assets

3 Months Ended

Mar. 31, 2019

Goodwill and Acquired Intangible Assets

Goodwill and Acquired Intangible Assets

14. Goodwill and Acquired Intangible Assets

As of March 31, 2019, the carrying amount of goodwill was $1.3 million. The following is a rollforward of the Company’s goodwill balance (in thousands):


	Goodwill
Balance as of December 31, 2018	$	1.3
Goodwill acquired		—
Balance as of March 31, 2019	$	1.3

Purchased intangible assets consist of the following (in thousands):


	Estimated	March 31, 2019
	Useful	Gross				Net
	Life	Carrying		Accumulated		Carrying
	(in years)	Value		Amortization		Value
Developed technology	7	$	1,650	$	(471)	$	1,179
Customer relationships	10		1,250		(261)		989
Trade names	3		50		(20)		30
Total		$	2,950	$	(752)	$	2,198

The Company recorded amortization expense of $0.2 million and $0.1 million, for the three months ended March 31, 2019 and 2018, respectively. Amortization relating to developed technology is recorded within research and development expense, amortization of customer relationships is recorded within sales and marketing expenses, and amortization of trade names is recorded within general and administrative expenses.

Future estimated amortization expense of acquired intangibles as of March 31, 2019 is as follows (in thousands):


For the Years Ended December 31,	Estimated Amortization Expense
2019	$	431
2020		500
2021		403
2022		320
2023		238
Thereafter		306
	$	2,198

- Definition

The entire disclosure for the aggregate amount of goodwill and a description of intangible assets, which may include (a) for amortizable intangible assets (also referred to as finite-lived intangible assets), the carrying amount, the amount of any significant residual value, and the weighted-average amortization period, (b) for intangible assets not subject to amortization (also referred to as indefinite-lived intangible assets), the carrying amount, and (c) the amount of research and development assets acquired and written off in the period, including the line item in the income statement in which the amounts written off are aggregated, if not readily apparent from the income statement. Also discloses (a) for amortizable intangibles assets in total and by major class, the gross carrying amount and accumulated amortization, the total amortization expense for the period, and the estimated aggregate amortization expense for each of the five succeeding fiscal years, (b) for intangible assets not subject to amortization the carrying amount in total and by major class, and (c) for goodwill, in total and for each reportable segment, the changes in the carrying amount of goodwill during the period (including the aggregate amount of goodwill acquired, the aggregate amount of impairment losses recognized, and the amount of goodwill included in the gain (loss) on disposal of a reporting unit). If any part of goodwill has not been allocated to a reportable segment, discloses the unallocated amount and the reasons for not allocating. For each impairment loss recognized related to an intangible asset (excluding goodwill), discloses: (a) a description of the impaired intangible asset and the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method for determining fair value, (c) the caption in the income statement or the statement of activities in which the impairment loss is aggregated, and (d) the segment in which the impaired intangible asset is reported. For each goodwill impairment loss recognized, discloses: (a) a description of the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method of determining the fair value of the associated reporting unit, and (c) if a recognized impairment loss is an estimate not finalized and the reasons why the estimate is not final. May also disclose the nature and amount of any significant adjustments made to a previous estimate of an impairment loss.

+ References + Details

Related party transactions	3 Months Ended
Related party transactions	Mar. 31, 2019
Related party transactions
Related party transactions	15. Related party transactions bioMérieux is a customer and also a holder of the Company’s common stock. bioMérieux formerly also had a designee on the Company’s Board of Directors. On September 6, 2018, bioMérieux notified the Company that it was terminating the Amended JDLA. The termination of the agreement resulted in the immediate recognition of the remaining deferred revenue. The Company recognized revenue from bioMérieux related to the Amended JDLA of $0.0 million and $0.3 million in the three months ended March 31, 2019 and 2018, respectively. The Company entered into the License Agreement for certain intellectual property with Tufts. Tufts is a related party to the Company due to Tufts’ equity ownership in the Company and because a board member of the Company’s Board of Directors was affiliated with Tufts. During the three months ended March 31, 2019 and 2018, the Company recorded royalty expense of $0.2 million and $0.1 million, respectively, in cost of product revenue on the consolidated statements of operations and comprehensive loss. During the year ended December 31, 2017, Harvard University became a related party. Revenue recorded from sales to Harvard University were less than $0.1 million for each of the three months ended March 31, 2019 and 2018.

Subsequent events	3 Months Ended
Subsequent events	Mar. 31, 2019
Subsequent events
Subsequent events	16. Subsequent events On April 15, 2019, the Company signed Amendment 7 to the Loan Agreement, which extends the interest only payment period through July 1, 2021 and also extends the maturity date until October 1, 2021. As part of this Amendment 7 a “2019 End of Term Fee” for $50,000 was added to the Loan Agreement due on the earliest to occur of (i) the Term Loan Maturity Date, (ii) the date that the Company prepays the outstanding Secured Obligations and (iii) the date that the Secured Obligations become due and payable. In addition, the Company is required to pay the loan principal in five equal installments starting July 1, 2021 with the final principal payment to be made on October 1, 2021.

Significant accounting policies (Policies)

3 Months Ended

Mar. 31, 2019

Significant accounting policies

Principles of consolidation

Use of estimates

Business combinations

Restricted Cash

Recent accounting pronouncements

The Company recorded a decrease to the accumulated deficit of $0.4 million as of January 1, 2019 for the cumulative effect primarily related to the deferral of sales commissions .


											Prior to
	As										adoption of
	reported				Adjusted under		As reported				ASC 606
	December				ASC 606		March 31,				March 31,
	31, 2018		Adjustments		January 1, 2019		2019		Adjustments		2018
Assets:
Accounts receivable	$	6,792	$	47	$	6,839	$	7,303	$	(47)	$	7,256
Prepaid expenses and other current assets		2,330		288		2,618		2,502		26		2,528
Other non-current assets		536		19		555		550		(1)		549

Liabilities:
Deferred revenue		5,437		43		5,480		5,484		27		5,511
Deferred revenue, net of current portion		520		43		563		431		(2)		429

Stockholders’ equity:
Accumulated deficit	$	(175,888)	$	(440)	$	(176,328)	$	(184,853)	$	(47)	$	(184,900)


	For the three months ended March 31, 2019
					Under ASC
	Under ASC 606		Adjustment		605
Product revenue	$	9,547	$	(33)	$	9,514
Service revenue		2,790		105		2,895
COGS		2,082		1		6,331
Gross profit		6,007		71		6,078
Selling general and administrative expenses		11,512		24		11,536
Net loss	$	(9,405)	$	47	$	(9,358)

The adoption of ASC 606 is discussed in further detail in Note 3.

There have been no other material changes to the significant accounting policies and recent accounting pronouncements previously disclosed in the 2018 Annual Report on Form 10‑K.

Significant accounting policies (Tables)

3 Months Ended

Mar. 31, 2019

ASU 2014-09

Revenue recognition

Schedule of impact on consolidated balance sheet and statement of operations due to adoption of ASU 606


											Prior to
	As										adoption of
	reported				Adjusted under		As reported				ASC 606
	December				ASC 606		March 31,				March 31,
	31, 2018		Adjustments		January 1, 2019		2019		Adjustments		2018
Assets:
Accounts receivable	$	6,792	$	47	$	6,839	$	7,303	$	(47)	$	7,256
Prepaid expenses and other current assets		2,330		288		2,618		2,502		26		2,528
Other non-current assets		536		19		555		550		(1)		549

Liabilities:
Deferred revenue		5,437		43		5,480		5,484		27		5,511
Deferred revenue, net of current portion		520		43		563		431		(2)		429

Stockholders’ equity:
Accumulated deficit	$	(175,888)	$	(440)	$	(176,328)	$	(184,853)	$	(47)	$	(184,900)


	For the three months ended March 31, 2019
					Under ASC
	Under ASC 606		Adjustment		605
Product revenue	$	9,547	$	(33)	$	9,514
Service revenue		2,790		105		2,895
COGS		2,082		1		6,331
Gross profit		6,007		71		6,078
Selling general and administrative expenses		11,512		24		11,536
Net loss	$	(9,405)	$	47	$	(9,358)

Revenue recognition (Tables)

3 Months Ended

Mar. 31, 2019

Revenue recognition

Schedule of disaggregated revenue


	Three Months Ended March 31, 2019
($in thousands)	NA		EMEA		Asia Pacific		Total
Product revenues
Instruments	$	1,397	$	1,145	$	874	$	3,416
Consumable and other products	$	3,619	$	2,088	$	424	$	6,131
Totals	$	5,016	$	3,233	$	1,298	$	9,547

Service and other revenues
Service-type warranties	$	689	$	234	$	37	$	960
Research services	$	1,504	$	—	$	—	$	1,504
Other services	$	201	$	108	$	17	$	326
Totals	$	2,394	$	342	$	54	$	2,790

Schedule of changes in deferred revenue from contracts with customers were as follows

Changes in deferred revenue from contracts with customers were as follows (in thousands):


	Three Months
	Ended March 31,
	2019
Balance at December 31, 2018	$	5,957
606 adoption adjustment		(86)
Deferral of revenue		1,004
Recognition of deferred revenue		(960)
Balance at March 31, 2019	$	5,915

Schedule of costs to obtain a contract

The change in the balance of costs to obtain a contract are as follows (in thousands):


	Three Months
	Ended March 31,
	2019
Balance at December 31, 2018	$	—
606 adoption adjustment		307
Deferral of costs to obtain a contract		194
Recognition of costs to obtain a contract		(170)
Balance at March 31, 2019	$	331

Net loss per share (Tables)

3 Months Ended

Mar. 31, 2019

Net loss per share

Schedule of outstanding potentially dilutive securities that have been excluded in the calculation of diluted net loss per share


	March 31,
	2019	2018
Unvested restricted common stock and restricted stock units	419,716	153,428
Outstanding stock options	2,802,343	2,450,846
Outstanding warrants	76,041	76,041
Total	3,298,100	2,680,315

Fair value of financial instruments (Tables)

3 Months Ended

Mar. 31, 2019

Fair value of financial instruments

Schedule of fair value measurements

Fair value measurements as of March 31, 2019 are as follows (in thousands):


			Quoted prices
			in active		Significant other		Significant
			markets		observable		unobservable inputs
Description	Total		(Level 1)		inputs (Level 2)		(Level 3)
Financial assets
Cash equivalents	$	31,958	$	31,958	$	—	$	—
Note receivable		150		—		—		150
	$	32,108	$	31,958	$	—	$	150

Fair value measurements as of December 31, 2018 are as follows (in thousands):


			Quoted prices		Significant other		Significant
			in active		observable		Significant
			markets		inputs (Level 2)		unobservable inputs
Description	Total		(Level 1)		(Level 2)		(Level 3)
Financial assets
Cash equivalents	$	42,608	$	42,608	$	—	$	—
Note receivable		150		—		—		150
	$	42,758	$	42,608	$	—	$	150

Inventory (Tables)

3 Months Ended

Mar. 31, 2019

Inventory

Summary of inventory

Inventory consists of the following (in thousands):


	March 31,		December 31,
	2019		2018
Raw Materials	$	2,999	$	1,546
Work in process		2,662		2,331
Finished goods		2,081		2,068
Total	$	7,742	$	5,945

Other accrued expenses (Tables)

3 Months Ended

Mar. 31, 2019

Other accrued expenses

Summary of other accrued expenses

Other accrued expenses consist of the following (in thousands):


	March 31,		December 31,
	2019		2018
Accrued inventory	$	795	$	599
Accrued royalties		399		323
Accrued professional services		851		723
Accrued development costs		1,067		795
Accrued other		662		689
Total accrued expenses	$	3,774	$	3,129

Warrants, stock-based compensation, stock options, restricted stock and restricted stock units (Tables)

3 Months Ended

Mar. 31, 2019

Warrants, stock-based compensation, stock options, restricted stock and restricted stock units

Summary of share-based compensation expense for all stock awards

Share‑based compensation expense for all stock awards consists of the following (in thousands):


	Three months ended March 31,
	2019		2018
Cost of product revenue	$	17	$	10
Cost of service and other revenue		60		32
Research and development		168		71
General and administrative		1,039		523
Total	$	1,284	$	636

Summary of stock option activity


		Weighted-average		Remaining contractual	Aggregate intrinsic value
	Options	exercise price		life (in years)	(in thousands)
Outstanding at December 31, 2018	2,476,911	$	9.65	7.73		22,108
Granted	460,674	$	21.32
Exercised	(78,712)	$	6.38
Cancelled	(56,530)	$	13.78
Outstanding at March 31, 2019	2,802,343	$	11.57	7.90		39,954
Vested and expected to vest at March 31, 2019	2,802,343	$	11.57	7.90		39,954
Exercisable at March 31, 2019	1,233,379	$	6.69	6.55		23,608

Summary of restricted stock units activity


		Weighted-average
		grant date
		fair value
	Shares	per share
Unvested RSUs as of December 31, 2018	321,662	$	15.84
Granted	130,085	$	21.37
Vested	(23,649)	$	16.36
Cancelled	(8,382)	$	18.88
Unvested RSUs as of March 31, 2019	419,716	$	17.46

Commitments and contingencies (Tables)

3 Months Ended

Mar. 31, 2019

Commitments and contingencies

Schedule of minimum future rent payments under the lease agreement

As of March 31, 2019, the minimum future rent payments under the lease agreements are as follows (in thousands):


2019	$	831
2020		2,013
2021		3,290
2022		3,372
2023 and Forward		29,207
	$	38,713

Notes payable (Tables)

3 Months Ended

Mar. 31, 2019

Notes payable

Schedule of debt payment obligations due based on principal payments

As of March 31, 2019, debt payment obligations due based on principal payments are as follows (in thousands):


2019	$	—
2020		—
2021		7,763
	$	7,763

Goodwill and Acquired Intangible Assets (Tables)

3 Months Ended

Mar. 31, 2019

Goodwill and Acquired Intangible Assets

Rollforward of goodwill balance

The following is a rollforward of the Company’s goodwill balance (in thousands):


	Goodwill
Balance as of December 31, 2018	$	1.3
Goodwill acquired		—
Balance as of March 31, 2019	$	1.3

Summary of intangible assets

Purchased intangible assets consist of the following (in thousands):


	Estimated	March 31, 2019
	Useful	Gross				Net
	Life	Carrying		Accumulated		Carrying
	(in years)	Value		Amortization		Value
Developed technology	7	$	1,650	$	(471)	$	1,179
Customer relationships	10		1,250		(261)		989
Trade names	3		50		(20)		30
Total		$	2,950	$	(752)	$	2,198

Schedule of future estimated amortization expense of acquired intangibles

Future estimated amortization expense of acquired intangibles as of March 31, 2019 is as follows (in thousands):


For the Years Ended December 31,	Estimated Amortization Expense
2019	$	431
2020		500
2021		403
2022		320
2023		238
Thereafter		306
	$	2,198

Organization and operations (Details) $ / shares in Units, $ in Thousands		1 Months Ended
	Dec. 04, 2017	Dec. 31, 2017 USD ($) $ / shares shares	Mar. 31, 2019 USD ($) shares	Dec. 31, 2018 USD ($) shares	Mar. 31, 2018 USD ($)	Dec. 11, 2017 shares
Initial Public Offering
Cash and cash equivalents \| $			$ 33,972	$ 44,429	$ 65,231
Common stock authorized (in shares)			120,000,000	120,000,000		120,000,000
Preferred stock authorized (in shares)						5,000,000
Common stock
Initial Public Offering
Aggregate net proceeds from IPO \| $		$ 65,600
Reverse stock split ratio	0.311
Initial Public Offering
Initial Public Offering
Carrying value of preferred stock, notes and warrants reclassified as common stock and additional paid-in capital \| $		$ 143,300
Preferred stock converted to common stock (in shares)		14,185,744
Initial Public Offering \| Common stock
Initial Public Offering
Issuance of stock, net of issuance costs (in shares)		4,916,480
Shares issued (in dollars per share) \| $ / shares		$ 15.00

Significant accounting policies - Recent accounting pronouncements (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Jan. 01, 2019	Dec. 31, 2018	Sep. 30, 2018	Sep. 30, 2016
Assets:
Accounts receivable	$ 7,303		$ 6,839	$ 6,792
Prepaid expenses and other current assets	2,502		2,618	2,330
Other assets	550		555	536
Liabilities:
Deferred revenue	5,484		5,480	5,437
Deferred revenue, net of current portion	431		563	520
Stockholders' equity:
Accumulated deficit	(184,853)		(176,328)	(175,888)
Revenue	12,337	$ 7,521
Total costs of goods sold and services	6,330	4,349
Gross profit	6,007	3,172
Selling, general and administrative expense	11,512	6,691
Net loss	(9,405)	(7,202)
Restricted cash	1,019			$ 1,000
Minority interest in preferred stock in privately held company
Stockholders' equity:
Purchase price of investment						$ 300
Investment in a convertible notes of a privately held company
Stockholders' equity:
Investment principle amount					$ 200
Product revenue
Stockholders' equity:
Revenue	9,547	4,745
Total costs of goods sold and services	4,248	2,773
Service and other revenue
Stockholders' equity:
Revenue	2,790	2,507
Total costs of goods sold and services	2,082	$ 1,576
Adjustments
Assets:
Accounts receivable	(47)		47
Prepaid expenses and other current assets	26		288
Other assets	(1)		19
Liabilities:
Deferred revenue	27		43
Deferred revenue, net of current portion	(2)		43
Stockholders' equity:
Accumulated deficit	(47)		$ (440)
Gross profit	71
Selling, general and administrative expense	24
Net loss	47
Adjustments \| Product revenue
Stockholders' equity:
Revenue	(33)
Adjustments \| Service and other revenue
Stockholders' equity:
Revenue	105
Total costs of goods sold and services	1
Balances without adoption of ASU 606
Assets:
Accounts receivable	7,256
Prepaid expenses and other current assets	2,528
Other assets	549
Liabilities:
Deferred revenue	5,511
Deferred revenue, net of current portion	429
Stockholders' equity:
Accumulated deficit	(184,900)
Gross profit	6,078
Selling, general and administrative expense	11,536
Net loss	(9,358)
Balances without adoption of ASU 606 \| Product revenue
Stockholders' equity:
Revenue	9,514
Balances without adoption of ASU 606 \| Service and other revenue
Stockholders' equity:
Revenue	2,895
Total costs of goods sold and services	$ 6,331

Revenue recognition (Details)	3 Months Ended
Revenue recognition (Details)	Mar. 31, 2019 customer
Revenue recognition
Minimum number of customers	200
Minimum
Revenue recognition
Period of payment	30 days
Maximum
Revenue recognition
Period of payment	45 days

Revenue recognition - Disaggregated revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Revenue recognition
Total revenue	$ 12,337	$ 7,521
Product revenue
Revenue recognition
Total revenue	9,547	4,745
Product revenue \| NA
Revenue recognition
Total revenue	5,016
Product revenue \| EMEA
Revenue recognition
Total revenue	3,233
Product revenue \| Asia Pacific
Revenue recognition
Total revenue	1,298
Instruments
Revenue recognition
Total revenue	3,416
Instruments \| NA
Revenue recognition
Total revenue	1,397
Instruments \| EMEA
Revenue recognition
Total revenue	1,145
Instruments \| Asia Pacific
Revenue recognition
Total revenue	874
Consumable and other product
Revenue recognition
Total revenue	6,131
Consumable and other product \| NA
Revenue recognition
Total revenue	3,619
Consumable and other product \| EMEA
Revenue recognition
Total revenue	2,088
Consumable and other product \| Asia Pacific
Revenue recognition
Total revenue	424
Service and other revenue
Revenue recognition
Total revenue	2,790	2,507
Service and other revenue \| NA
Revenue recognition
Total revenue	2,394
Service and other revenue \| EMEA
Revenue recognition
Total revenue	342
Service and other revenue \| Asia Pacific
Revenue recognition
Total revenue	54
Service-type warranties
Revenue recognition
Total revenue	960
Service-type warranties \| NA
Revenue recognition
Total revenue	689
Service-type warranties \| EMEA
Revenue recognition
Total revenue	234
Service-type warranties \| Asia Pacific
Revenue recognition
Total revenue	37
Research services
Revenue recognition
Total revenue	1,504
Research services \| NA
Revenue recognition
Total revenue	1,504
Other services
Revenue recognition
Total revenue	326
Other services \| NA
Revenue recognition
Total revenue	201
Other services \| EMEA
Revenue recognition
Total revenue	108
Other services \| Asia Pacific
Revenue recognition
Total revenue	$ 17
Collaboration and license revenue
Revenue recognition
Total revenue		$ 269

Revenue recognition - Future performance obligations (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019 USD ($)
Transaction Price Allocated to Future Performance Obligations
Amount of transaction price allocated to performance obligations	$ 5.9
Service-type warranties and research services
Transaction Price Allocated to Future Performance Obligations
Amount of transaction price allocated to performance obligations	3.6
Undelivered licenses of intellectual property
Transaction Price Allocated to Future Performance Obligations
Amount of transaction price allocated to performance obligations	1.7
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-04-01
Transaction Price Allocated to Future Performance Obligations
Amount of transaction price allocated to performance obligations	$ 2.6
Revenue recognition period for remaining performance obligation	12 months

Revenue recognition - Changes in deferred revenue from contracts with customers (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($)
Changes in deferred revenue from contracts with customers
Balance at beginning of period	$ 5,957
606 adoption adjustment	(86)
Deferral of revenue	1,004
Recognition of deferred revenue	(960)
Balance at end of period	$ 5,915

Revenue recognition - Costs to obtain a contract (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($)
Change in the balance of costs to obtain a contract
606 adoption adjustment	$ 307
Deferral of costs to obtain a contract	194
Recognition of costs to obtain a contract	(170)
Balance at end of period	$ 331

Revenue recognition - Practical expedients (Details)	3 Months Ended
Revenue recognition - Practical expedients (Details)	Mar. 31, 2019
Revenue recognition
Revenue, Practical Expedient, Financing Component [true/false]	true
Revenue, Practical Expedient, Remaining Performance Obligation [true/false]	true

Net loss per share (Details) - shares	3 Months Ended
Net loss per share (Details) - shares	Mar. 31, 2019	Mar. 31, 2018
Net loss per share
Number of dilutive securities excluded in the calculation of diluted net loss per share	3,298,100	2,680,315
Common stock
Net loss per share
Obligation to issue warrants, in shares	93,341	93,341
Unvested restricted common stock and restricted stock units
Net loss per share
Number of dilutive securities excluded in the calculation of diluted net loss per share	419,716	153,428
Outstanding stock options
Net loss per share
Number of dilutive securities excluded in the calculation of diluted net loss per share	2,802,343	2,450,846
Warrants
Net loss per share
Number of dilutive securities excluded in the calculation of diluted net loss per share	76,041	76,041

Fair value measurements (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Cash equivalents	$ 31,958	$ 42,608
Note receivable	150	150
Total	32,108	42,758
Level 1
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Cash equivalents	31,958	42,608
Total	31,958	42,608
Level 3
Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]
Note receivable	150	150
Total	$ 150	$ 150

Inventory (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Inventory
Raw Materials	$ 2,999	$ 1,546
Work in process	2,662	2,331
Finished goods	2,081	2,068
Total	$ 7,742	$ 5,945

Investments (Details) - USD ($) $ in Millions	3 Months Ended
Investments (Details) - USD ($) $ in Millions	Mar. 31, 2019	Sep. 30, 2018	Sep. 30, 2016
Minority interest in preferred stock in privately held company
Schedule of Cost-method Investments [Line Items]
Purchase price of investment			$ 0.3
Impairment on investments	$ 0.0
Investment in a convertible notes of a privately held company
Schedule of Cost-method Investments [Line Items]
Investment principle amount		$ 0.2

Other accrued expenses (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Other accrued expenses
Accrued inventory	$ 795	$ 599
Accrued royalties	399	323
Accrued professional services	851	723
Accrued development costs	1,067	795
Accrued other	662	689
Total accrued expenses	$ 3,744	$ 3,129

Warrants, stock-based compensation, stock options, restricted stock and restricted stock units - Warrants (Details) - Warrants	3 Months Ended
	Mar. 31, 2019 shares
Number outstanding
Issued (in shares)	0
Outstanding at the end of the period (in shares)	76,041

Warrants, stock-based compensation, stock options, restricted stock and restricted stock units - Share-based compensation expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Warrants, stock-based compensation, stock options, restricted stock and restricted stock units
Share-based compensation expense	$ 1,284	$ 636
Cost of product revenue
Warrants, stock-based compensation, stock options, restricted stock and restricted stock units
Share-based compensation expense	17	10
Cost of service and other revenue
Warrants, stock-based compensation, stock options, restricted stock and restricted stock units
Share-based compensation expense	60	32
Research and development
Warrants, stock-based compensation, stock options, restricted stock and restricted stock units
Share-based compensation expense	168	71
General and administrative
Warrants, stock-based compensation, stock options, restricted stock and restricted stock units
Share-based compensation expense	$ 1,039	$ 523

Warrants, stock-based compensation, stock options, restricted stock and restricted stock units - Stock-based award plans (Details) - shares	Jan. 01, 2019	Mar. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
2007 Plan
Warrants, stock-based compensation, stock options, restricted stock and restricted stock units
Common stock available for future awards (in shares)		0
2017 Plan
Warrants, stock-based compensation, stock options, restricted stock and restricted stock units
Shares authorized under the plan (in shares)				1,042,314
Shares available for grant under the plan (in shares)		1,373,307
Annual increase in the shares available for grant under the plan (as a percent of shares of common stock outstanding)		4.00%
Increase in the shares available for grant under the plan (in shares)	894,761
2017 ESPP
Warrants, stock-based compensation, stock options, restricted stock and restricted stock units
Shares authorized under the plan (in shares)		649,233
Shares available for grant under the plan (in shares)		629,173
Annual increase in the shares available for grant under the plan (as a percent of shares of common stock outstanding)		1.00%
Increase in the shares available for grant under the plan (in shares)	223,690
Outstanding stock options
Warrants, stock-based compensation, stock options, restricted stock and restricted stock units
Options outstanding (in shares)		2,802,343	2,476,911
Outstanding stock options \| 2007 Plan
Warrants, stock-based compensation, stock options, restricted stock and restricted stock units
Options outstanding (in shares)		1,691,565
Common stock issued and outstanding pursuant to the exercise of options (in shares)		1,103,535
Outstanding stock options \| 2017 Plan
Warrants, stock-based compensation, stock options, restricted stock and restricted stock units
Shares authorized under the plan (in shares)				2,490,290
Restricted and unrestricted stock awards \| 2007 Plan
Warrants, stock-based compensation, stock options, restricted stock and restricted stock units
Common stock issued and outstanding pursuant to restricted or unrestricted stock awards (in shares)		0

Warrants, stock-based compensation, stock options, restricted stock and restricted stock units - Stock options (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Aggregate intrinsic value
Share-based compensation expense	$ 1,284	$ 636
Outstanding stock options
Warrants, stock-based compensation, stock options, restricted stock and restricted stock units
Options expiration period (in years)	10 years
Number outstanding
Outstanding at the beginning of the period (in shares)	2,476,911
Granted (in shares)	460,674
Exercised (in shares)	(78,712)
Cancelled or forfeited (in shares)	(56,530)
Outstanding at the end of the period (in shares)	2,802,343		2,476,911
Vested and expected to vest at the end of the period (in shares)	2,802,343
Exercisable at the end of the period (in shares)	1,233,379
Weighted-average exercise price
Outstanding at the beginning of the period (in dollars per share)	$ 9.65
Granted (in dollars per share)	21.32
Exercised (in dollars per share)	6.38
Cancelled or forfeited (in dollars per share)	13.78
Outstanding at the end of the period (in dollars per share)	11.57		$ 9.65
Vested and expected to vest at the end of the period (in dollars per share)	11.57
Exercisable at the end of the period (in dollars per share)	$ 6.69
Remaining contractual life
Outstanding (in years)	7 years 10 months 24 days		7 years 8 months 23 days
Vested and expected to vest at the end of the period (in years)	7 years 10 months 24 days
Exercisable at the end of the period (in years)	6 years 6 months 18 days
Aggregate intrinsic value
Outstanding	$ 39,954		$ 22,108
Vested and expected to vest at the end of the period	39,954
Exercisable at the end of the period	$ 23,608
Weighted-average fair value of options granted	$ 7.90	$ 8.72
Share-based compensation expense	$ 700	$ 700
Intrinsic value of stock options exercised	$ 1,200	$ 1,000
Outstanding stock options \| Subject to a four year vesting schedule with 25% vesting on the first anniversary and the remaining vesting ratably on a monthly basis over the remaining three years
Warrants, stock-based compensation, stock options, restricted stock and restricted stock units
Vesting period (in years)	4 years
Vesting percentage 1 (as a percent)	25.00%
Outstanding stock options \| Subject to vesting with 50% vesting on December 31, 2018 and December 31, 2019
Warrants, stock-based compensation, stock options, restricted stock and restricted stock units
Vesting period (in years)	3 years
Vesting percentage 1 (as a percent)	75.00%

Warrants, stock-based compensation, stock options, restricted stock and restricted stock units - Restricted stock (Details) - Restricted stock - shares	1 Months Ended		3 Months Ended
	Jan. 31, 2015	Dec. 31, 2014	Mar. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)			0
2007 Plan \| Director
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)		78,912
Vesting period (in years)		4 years
2007 Plan \| Executive
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	781,060
Vesting period (in years)	4 years
2007 Plan \| Executive \| Subject to a four year vesting schedule with 25% vesting on the first anniversary and the remaining vesting ratably on a monthly basis over the remaining three years
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage 1 (as a percent)	25.00%
2007 Plan \| Executive \| Subject to vesting with 50% vesting on December 31, 2018 and December 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period (in years)	3 years
Vesting percentage 1 (as a percent)	75.00%

Warrants, stock-based compensation, stock options, restricted stock and restricted stock units - Restricted stock units (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Weighted-average grant date fair value per share
Share-based compensation expense	$ 1,284	$ 636
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted common stock issued (in shares)	130,085
Number of restricted stock units
Unvested restricted common stock at the beginning of the period (in shares)	321,662
Granted (in shares)	130,085
Vested (in shares)	(23,649)
Cancelled (in shares)	(8,382)
Unvested restricted common stock at the end of the period (in shares)	419,716
Weighted-average grant date fair value per share
Unvested restricted common stock at the beginning of the period (in dollars per share)	$ 15.84
Granted (in dollars per share)	21.37
Vested (in dollars per share)	16.36
Cancelled (in dollars per share)	18.88
Unvested restricted common stock at the end of the period (in dollars per share)	$ 17.46
Share-based compensation expense	$ 500	$ 200
Total unrecognized compensation cost related to unvested stock awards	$ 7,000
Period of recognition of unrecognized compensation cost	3 years 7 days
2017 Plan \| Restricted stock units \| Subject to a four year vesting schedule with 25% vesting on the first anniversary and the remaining vesting ratably on a monthly basis over the remaining three years
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted common stock issued (in shares)	82,463
Vesting period 1	4 years
Vesting period 2	3 years
Vesting percentage 1 (as a percent)	25.00%
Vesting percentage 2 (as a percent)	75.00%
Number of restricted stock units
Granted (in shares)	82,463
2017 Plan \| Restricted stock units \| Vesting on December 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted common stock issued (in shares)	15,890
Number of restricted stock units
Granted (in shares)	15,890
2017 Plan \| Restricted stock units \| Vesting on March 31, 2019 and remaining vesting evenly over 45 months thereafter
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted common stock issued (in shares)	31,731
Number of restricted stock units
Granted (in shares)	31,731
2017 Plan \| Restricted stock units \| Vesting on March 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted common stock issued (in shares)	1,983
Number of restricted stock units
Granted (in shares)	1,983
2017 Plan \| Restricted stock units \| Vests evenly over 45 months after vesting on March 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period 3	45 months

Commitments and contingencies - License agreements and Lease commitments (Details) - USD ($)		3 Months Ended
	Oct. 02, 2018	Mar. 31, 2019	Mar. 31, 2018
License agreements
Drawing capacity	$ 1,000,000
Letter of credit will be reduced at 41 months after the commencement date	750,000
Letter of credit will be reduced at 65 months after the commencement date	$ 250,000
Minimum future rent payments under the lease agreement
2019		$ 831,000
2020		2,013,000
2021		3,290,000
2022		3,372,000
2022 and Forward		29,207,000
Total		38,713,000
Rent expense		1,000,000	$ 300,000
Tufts
License agreements
Royalty expense		200,000	100,000
Other licenses
License agreements
Annual minimum royalty to be paid under the license agreement		50,000
Other licenses \| Maximum
License agreements
Royalty expense		100,000	$ 100,000
Company headquarters
License agreements
Term of operating lease	137 months
Other non-current liabilities
Lease commitments
Deferred rent expense		6,300,000
Other accrued expenses \| Maximum
Lease commitments
Deferred rent expense		$ 100,000

Commitments and contingencies - Development and supply agreement and Legal contingencies (Details) - STRATEC Biomedical - Development and supply agreement $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2019 USD ($) $ / shares shares
Commitments and contingencies
Amount payable to counterparty	$ 1.5
Period to purchase minimum number of commercial units	7 years
Fee payable on shortfall of commercial units purchase	$ 10.9
Issuance of supply warrants on termination of agreement, number (in shares) \| shares	93,341
Issuance of supply warrants on termination of agreement, value per share (in dollars per share) \| $ / shares	$ 0.003214

Notes payable (Details) - USD ($) $ in Millions	3 Months Ended
Notes payable (Details) - USD ($) $ in Millions	Mar. 31, 2019	Oct. 02, 2018
Long Term Debt
Total facility available		$ 1.0
Loan agreement
Long Term Debt
Additional amounts available to borrow	$ 0.0
Loan agreement \| Minimum
Long Term Debt
Interest rate (as a percent)	8.25%
Prime rate \| Loan agreement
Long Term Debt
Margin on variable interest rate (as a percent)	(5.25%)

Notes payable - Debt payment obligations (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Debt payment obligations due based on principal payments
2021	$ 7,763
Debt payment obligations	7,763
Non-cash interest expense	100	$ 100
Leasehold improvement related to the new lease	$ 5,300

Collaboration and license arrangements (Details) $ in Thousands		1 Months Ended	3 Months Ended		12 Months Ended
	Sep. 06, 2018 USD ($)	Dec. 31, 2016 USD ($)	Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2015 USD ($) item agreement
Collaboration and license arrangements
Revenue			$ 12,337	$ 7,521
Joint development and license agreement
Collaboration and license arrangements
Consideration on collaboration activities			3,200
Revenue	$ 1,600
Evaluation and option agreements and license agreement
Collaboration and license arrangements
Revenue		$ 1,800
Number of agreements \| agreement						3
Number of fields for which the agreements were entered \| item						3
Non-refundable license fee		1,000				$ 2,000
Amount allocated to the option of the related field		$ 800
Deferred revenue			$ 1,700		$ 1,700
Exclusive agreement
Collaboration and license arrangements
Consideration on collaboration activities					$ 500

Employee benefit plans (Details) $ in Millions	3 Months Ended
Employee benefit plans (Details) $ in Millions	Mar. 31, 2019 USD ($)
Employee benefit plans
Contribution made to the 401 (k) Plan	$ 0.1

Goodwill and Acquired Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Rollforward of goodwill balance
Balance as of beginning of period	$ 1,308
Balance as of end of period	1,308
Purchased intangible assets
Gross Carrying Value	2,950
Accumulated Amortization	(752)
Net Carrying Value	2,198
Amortization expense	200	$ 100
Estimated amortization expense
2019	431
2020	500
2021	403
2022	320
2023	238
Thereafter	$ 306
Developed technology
Purchased intangible assets
Estimated Useful Life	7 years
Gross Carrying Value	$ 1,650
Accumulated Amortization	(471)
Net Carrying Value	$ 1,179
Customer relationships
Purchased intangible assets
Estimated Useful Life	10 years
Gross Carrying Value	$ 1,250
Accumulated Amortization	(261)
Net Carrying Value	$ 989
Trade names
Purchased intangible assets
Estimated Useful Life	3 years
Gross Carrying Value	$ 50
Accumulated Amortization	(20)
Net Carrying Value	$ 30

Related party transactions (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
bioMerieux \| Joint development and license agreement
Related party transactions
Related party revenue	$ 0.0	$ 0.3
Tufts \| License Agreement
Related party transactions
Royalty expense	0.2	0.1
Harvard University \| Maximum
Related party transactions
Related party revenue	$ 0.1	$ 0.1

Subsequent events (Details)	Apr. 15, 2019 USD ($) installment	Oct. 02, 2018 USD ($)
Subsequent events
Drawing capacity		$ 1,000,000
Company headquarters
Subsequent events
Term of operating lease		137 months
Amendment 7 to loan agreement \| Subsequent event
Subsequent events
Term fee	$ 50,000
Number of installments \| installment	5