Quanterix (QTRX) 10-K 5 Mar 21 2020 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2020	Mar. 01, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Document Period End Date	Dec. 31, 2020
Document Annual Report	true
Entity Registrant Name	Quanterix Corp
Document Transition Report	false
Entity File Number	001-38319
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	20-8957988
Entity Address, Address Line One	900 Middlesex Turnpike
Entity Address, City or Town	Billerica
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	01821
City Area Code	617
Local Phone Number	301-9400
Title of 12(g) Security	Common Stock, $0.001 par value per share
Trading Symbol	QTRX
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Icfr Auditor Attestation Flag	false
Entity Public Float			$ 234,000,000
Entity Common Stock, Shares Outstanding		36,267,609
Entity Central Index Key	0001503274
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Amendment Flag	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 181,584	$ 109,155
Accounts receivable (less allowance for doubtful accounts of $370 and $162 as of December 31, 2020 and December 31, 2019, respectively; including $172 and $186 from related parties as of December 31, 2020 and December 31, 2019, respectively)	17,184	10,906
Inventory	14,856	10,463
Prepaid expenses and other current assets	5,981	2,137
Total current assets	219,605	132,661
Restricted cash	1,000	1,026
Property and equipment, net	13,912	12,047
Intangible assets, net	13,716	14,307
Goodwill	10,460	9,353
Right-of-use assets	11,995
Other non-current assets	357	557
Total assets	271,045	169,951
Current liabilities:
Accounts payable (including $14 and $36 to related parties as of December 31, 2020 and December 31, 2019, respectively)	6,799	5,777
Accrued compensation and benefits	10,777	6,570
Other accrued expenses (including $1,377 and $0 to related parties as of December 31, 2020 and December 31, 2019, respectively)	4,845	2,498
Deferred revenue (including $90 and $55 with related parties as of December 31, 2020 and December 31, 2019, respectively)	5,421	4,697
Current portion of long term debt	7,673	75
Short term lease liabilities	1,234
Other current liabilities	3,054	216
Total current liabilities	39,803	19,833
Deferred revenue, net of current portion	577	466
Long term debt, net of current portion		7,587
Long term lease liabilities	21,891
Other non-current liabilities	2,649	13,407
Total liabilities	64,920	41,293
Commitments and contingencies (Note 9)
Stockholders' equity:
Common stock, $0.001 par value: Authorized-120,000,000 shares as of December 31, 2020 and December 31, 2019; issued and outstanding - 31,796,544 and 28,112,201 shares as of December 31, 2020 and December 31, 2019, respectively	32	28
Additional paid-in capital	451,433	345,027
Accumulated other comprehensive income (loss)	2,434	(153)
Accumulated deficit	(247,774)	(216,244)
Total stockholders' equity	206,125	128,658
Total liabilities and stockholders' equity	$ 271,045	$ 169,951

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Condensed Consolidated Balance Sheets
Accounts receivable, reserve for doubtful accounts	$ 370	$ 162
Accounts receivable, related parties	172	186
Accounts payable, related parties	14	36
Other accrued expenses, related parties	1,377	0
Deferred revenue, current, related parties	$ 90	$ 55
Common stock, par value	$ 0.001	$ 0.001
Common stock, authorized shares	120,000,000	120,000,000
Common stock, shares issued	31,796,544	28,112,201
Common stock, shares outstanding	31,796,544	28,112,201

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Total revenue	$ 86,377	$ 56,734	$ 37,632
Costs of goods sold:
Total costs of goods sold, services, and licenses	38,195	29,898	19,684
Gross profit	48,182	26,836	17,948
Operating expenses:
Research and development (including related party activity of $268, $0, and $0 for the years ended December 31, 2020, 2019, and 2018, respectively)	20,174	16,190	15,805
Selling, general, and administrative (including related party activity of $36, $0, and $0 for the years ended December 31, 2020, 2019, and 2018)	59,592	52,246	33,693
Total operating expenses	79,766	68,436	49,498
Loss from operations	(31,584)	(41,600)	(31,550)
Interest income (expense), net	(273)	627	46
Other expense, net	(49)	(10)	(7)
Loss before income taxes	(31,906)	(40,983)	(31,511)
Income tax benefit (provision)	376	187	(25)
Net loss	$ (31,530)	$ (40,796)	$ (31,536)
Net loss per share, basic and diluted	$ (1.07)	$ (1.63)	$ (1.43)
Weighted-average common shares outstanding, basic and diluted	29,589,132	25,090,708	21,994,317
Product revenue
Total revenue	$ 44,017	$ 40,491	$ 23,365
Costs of goods sold:
Total costs of goods sold, services, and licenses	25,950	20,900	12,729
Service and other revenue
Total revenue	24,129	16,059	12,117
Costs of goods sold:
Total costs of goods sold, services, and licenses	11,245	8,998	6,955
Collaboration and license revenue
Total revenue	11,809	$ 184	$ 2,150
Costs of goods sold:
Total costs of goods sold, services, and licenses	1,000
Grant revenue
Total revenue	$ 6,422

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Operations (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Related party activity research and development expenses	$ 268	$ 0	$ 0
Related party activity in selling, general and administrative expenses	36	0	0
Product revenue
Related party revenue	580	720	294
Cost of product revenue, related party activity	205	234	191
Service and other revenue
Related party revenue	202	118	149
Cost of product revenue, related party activity	52	0	0
Collaboration and license revenue
Related party revenue	0	0	2,150
Cost of product revenue, related party activity	$ 1,000	$ 0	$ 0

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Condensed Consolidated Statements of Comprehensive Income (Loss)
Net loss	$ (31,530)	$ (40,796)	$ (31,536)
Other comprehensive income (loss):
Cumulative translation adjustment	2,587	(153)
Total other comprehensive income (loss)	2,587	(153)
Comprehensive income (loss)	$ (28,943)	$ (40,949)	$ (31,536)

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating activities
Net loss	$ (31,530)	$ (40,796)	$ (31,536)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization expense	4,312	3,009	1,352
Inventory step-up amortization	722	611
Reduction in the carrying amounts of right-of-use assets	245
Stock-based compensation expense	10,099	6,388	4,884
Non-cash interest expense	86	89	170
Loss (gain) on disposal of fixed assets	171	140	(14)
Changes in operating assets and liabilities:
Accounts receivable	(6,240)	(3,365)	(983)
Prepaid expenses and other assets	(3,927)	289	(1,828)
Inventory	(5,119)	(3,447)	(1,603)
Other non-current assets	198	(21)	267
Accounts payable	649	621	1,318
Accrued compensation and benefits, other accrued expenses and other current liabilities	6,219	822	1,101
Contract acquisition costs	87	336
Operating lease liabilities	316
Other non-current liabilities	(488)	9,845
Deferred revenue	835	(708)	(1,849)
Net cash used in operating activities	(23,365)	(26,187)	(28,721)
Investing activities
Purchases of property and equipment	(3,930)	(10,847)	(1,518)
Acquisitions, net of cash acquired		(14,529)	(3,801)
Proceeds from RADx grant on assets purchased	3,304
Purchase of Investments			(150)
Proceeds from sale of assets			15
Net cash used in investing activities	(626)	(25,376)	(5,454)
Financing activities
Proceeds from sale of common stock, net of issuance costs			(20)
Proceeds from stock options exercised	4,019	2,820	1,871
Proceeds from ESPP purchase	888	879
Payments on notes payable	(75)	(50)	(1,929)
Net cash provided by (used in) financing activities	96,236	116,197	(78)
Net increase (decrease) in cash and cash equivalents	72,245	64,634	(34,253)
Effect of foreign currency exchange rate on cash	158	118
Cash, restricted cash, and cash equivalents at beginning of period	110,181	45,429	79,682
Cash, restricted cash, and cash equivalents at end of period	182,584	110,181	45,429
Supplemental cash flow information
Cash paid for interest	625	656	606
Purchases of property and equipment included in accounts payable	1,029	164	78
Purchases of property and equipment included in other non-current liabilities		5,468
191,152 shares of common stock issued in connection with the acquisition of UmanDiagnostics AB		7,572
Fair value of common stock warrants exercised and reclassified as shares of common stock			196
Reconciliation of cash, cash equivalents, and restricted cash:
Total cash, cash equivalents, and restricted cash	110,181	110,181	$ 45,429
At-the-market offering
Financing activities
Sale of common stock in at-the-market offering, net		48,019
Underwritten public offering
Financing activities
Sale of common stock in at-the-market offering, net	$ 91,404	$ 64,529

Condensed Consolidated Statem_5

Condensed Consolidated Statements of Cash Flows (Parenthetical) - shares	Dec. 31, 2020	Aug. 01, 2019
Common stock shares consideration	191,152
UmanDiagnostics AB Acquisition
Common stock shares consideration		191,152

Condensed Consolidated Statem_6

Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Common stockUnderwritten public offering	Common stockAt-the-market offering	Common stock	Additional paid-in capitalUnderwritten public offering	Additional paid-in capitalAt-the-market offering	Additional paid-in capital	Accumulated other comprehensive income (loss)Underwritten public offering	Accumulated other comprehensive income (loss)	Accumulated deficit	Underwritten public offering	At-the-market offering	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						1,871						1,871
Exercise of common stock options and vesting restricted stock (in shares)			645,277
Common stock issuance offering costs						(20)						(20)
Stock-based compensation expense						4,884						4,884
Net loss									(31,536)			(31,536)
Ending Balance at Dec. 31, 2018			$ 22			216,931			(175,888)			41,065
Ending Balance (in shares) at Dec. 31, 2018			22,369,036
Increase (Decrease) in Stockholders' Equity
Exercise of common stock warrants (in shares)			45,690
Exercise of common stock options and vesting restricted stock						2,820						2,820
Exercise of common stock options and vesting restricted stock (in shares)			550,734
Sale of common stock	$ 3	$ 2		$ 64,526	$ 48,017					$ 64,529	$ 48,019
Sale of common stock (in shares)	2,732,673	2,186,163
Issuance of shares for the acquisition of UmanDiagnostics AB			$ 1			5,467						5,468
Issuance of shares for the acquisition of UmanDiagnostics AB (in shares)			191,152
Stock-based compensation expense						6,388						6,388
Employee stock purchase plan						878						878
Employee stock purchase plan (in shares)			36,753
Cumulative translation adjustment												(153)
Net loss									(40,796)			(40,796)
Ending Balance at Dec. 31, 2019			$ 28			345,027		$ (153)	(216,244)			128,658
Ending Balance (in shares) at Dec. 31, 2019			28,112,201
Increase (Decrease) in Stockholders' Equity
Cumulative-effect adjustment for the adoption of ASC 606									440			440
Accumulated other comprehensive income								(153)				(153)
Exercise of common stock options and vesting restricted stock			$ 1			4,018						4,019
Exercise of common stock options and vesting restricted stock (in shares)			589,723
Sale of common stock	$ 3			$ 91,401						91,404
Sale of common stock (in shares)	3,048,774
Stock-based compensation expense						10,099						10,099
Employee stock purchase plan						888						888
Employee stock purchase plan (in shares)			45,846
Cumulative translation adjustment							$ 2,587			$ 2,587		2,587
Net loss									(31,530)			(31,530)
Ending Balance at Dec. 31, 2020			$ 32			$ 451,433		$ 2,434	$ (247,774)			206,125
Ending Balance (in shares) at Dec. 31, 2020			31,796,544
Increase (Decrease) in Stockholders' Equity
Accumulated other comprehensive income												$ 2,434

Organization and operations

Organization and operations	12 Months Ended
	Dec. 31, 2020
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 its 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 the Company’s Simoa platforms have also demonstrated applicability across other testing applications, including detection of nucleic acids and small molecules. The Company launched its first immunoassay platform, the Simoa HD-1, in 2014. The HD-1 is 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 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. In July 2019, the Company launched the Simoa HD-X, an upgraded version of the Simoa HD-1 which replaces the HD-1. The HD-X has been designed to deliver significant productivity and operational efficiency improvements, as well as greater user flexibility. The Company began shipping and installing HD-X instruments at customer locations in the third quarter of 2019. The Company also performs research services on behalf of customers to apply the Simoa technology to specific customer needs. The Company's customers are primarily 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 acquired UmanDiagnostics AB (Uman), a Swedish company located in Umeå, Sweden, in August 2019. The acquisition closed with respect to 95% of the outstanding shares of capital stock of Uman on July 1, 2019 and with respect to the remaining 5% of the outstanding shares of capital stock of Uman on August 1, 2019. Uman supplies neurofilament light (Nf-L) antibodies and ELISA kits, which are widely recognized by researchers and biopharmaceutical and diagnostics companies world-wide as the premier solution for the detection of Nf-L to advance the development of therapeutics and diagnostics for neurodegenerative conditions. With the acquisition of Uman, the Company has secured a long-term source of supply for a critical technology. “At-the-market offering” On March 19, 2019, the Company entered into a Sales Agreement (the Sales Agreement) with Cowen and Company, LLC (Cowen) with respect to an “at-the-market” offering program under which the Company could offer and sell, from time to time at its sole discretion, shares of its common stock, par value $0.001 per share, having an aggregate offering price of up to $50.0 million through Cowen as its sales agent. On June 5, 2019, the Company issued approximately 2.2 million shares of common stock at an average stock price of $22.73 per share pursuant to the terms of the Sales Agreement. The “at-the-market” offering resulted in gross proceeds of $49.7 million. The Company incurred $1.7 million in issuance costs associated with the “at-the-market” offering, resulting in net proceeds to the Company of $48.0 million. On August 6, 2020, the Company delivered written notice to Cowen to terminate the Sales Agreement, which termination the parties agreed to make immediately effective. Underwritten public offering On August 8, 2019, the Company entered into an underwriting agreement with J.P. Morgan Securities LLC and SVB Leerink LLC (Leerink), as representatives of the several underwriters, relating to an underwritten public offering of approximately 2.7 million shares of the Company’s common stock, par value $0.001 per share. The underwritten public offering resulted in gross proceeds of $69.0 million. The Company incurred $4.5 million in issuance costs associated with the underwritten public offering, resulting in net proceeds to the Company of $64.5 million. On August 6, 2020, the Company entered into an underwriting agreement with Leerink and Cowen, as representatives of the several underwriters, relating to an underwritten public offering of approximately 3.0 million shares of the Company’s common stock, par value $0.001 per share. The underwritten public offering resulted in gross proceeds of $97.6 million. The Company incurred $6.2 million in issuance costs associated with the underwritten public offering, resulting in net proceeds to the Company of $91.4 million. Liquidity The Company has recognized annual losses from operations since inception and has an accumulated deficit of $247.8 million at December 31, 2020 and the Company incurred a net loss of $31.5 million, $40.8 million, and $31.5 million for the years ended December 31, 2020, 2019, and 2018, respectively. Prior to the Company’s Initial Public Offering (IPO) in December 2017, the Company had funded its operations principally from issuances of preferred stock, debt financings, grants, product and service sales and development and license agreements. At December 31, 2020, the Company had $181.6 million of unrestricted cash and cash equivalents. The Company expects the current cash balance will be sufficient to fund operations for a period of at least one year from the date the consolidated financial statements are issued. There can be no assurances, however, that no additional funding will be required or that additional funding will be available on terms acceptable to the Company, or at all.

Significant accounting policies

Significant accounting policies	12 Months Ended
	Dec. 31, 2020
Significant accounting policies
Significant accounting policies	2. Significant accounting policies Principles of consolidation The 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 assets acquired and liabilities assumed in acquisitions, valuation allowances recorded against deferred tax assets, and valuation of inventory. Actual results could differ from those estimates. 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 Accounting Standards Codification (ASC) Topic 606 Revenue from Contracts with Customers 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 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 recognized revenues from sales- or usage based royalties related to the Company’s licensing technology and intellectual property. 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 recorded sales- or usage-based royalty revenue for the years ended December 31, 2020 and 2019 related to the intellectual property licensed by Uman. The Company recognizes revenues from sales- or usage based royalty revenue at the later of when the sales or usage occurs; and the satisfaction or partial satisfaction of the performance obligation to which the royalty has been allocated. ​ 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. Occasionally the Company provides extended payment terms or financing arrangements to 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: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ December 31, 2020 (in thousands) NA EMEA Asia Pacific Total Product revenues ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Instruments $ 8,680 ​ $ 4,332 ​ $ 3,594 ​ $ 16,606 Consumable and other products ​ 14,305 ​ ​ 10,854 ​ ​ 2,252 ​ ​ 27,411 Totals $ 22,985 $ 15,186 $ 5,846 $ 44,017 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Service and other revenues ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Service-type warranties $ 3,171 ​ $ 1,543 ​ $ 207 ​ $ 4,921 Research services ​ 15,011 ​ ​ 2,225 ​ ​ 737 ​ 17,973 Other services ​ 700 ​ ​ 435 ​ ​ 100 ​ ​ 1,235 Totals ​ $ 18,882 ​ $ 4,203 ​ $ 1,044 ​ $ 24,129 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Collaboration and license revenue ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Collaboration and license revenue ​ $ 11,685 ​ $ 124 ​ $ — ​ $ 11,809 Totals $ 11,685 $ 124 $ — $ 11,809 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ December 31, 2019 (in thousands) NA EMEA Asia Pacific Total Product revenues ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Instruments $ 6,250 $ 5,243 $ 3,393 $ 14,886 Consumable and other products ​ 14,148 ​ 9,674 ​ 1,783 ​ 25,605 Totals $ 20,398 $ 14,917 $ 5,176 $ 40,491 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Service and other revenues ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Service-type warranties $ 3,139 $ 1,323 $ 171 $ 4,633 Research services ​ 8,845 ​ 704 ​ 456 ​ 10,005 Other services ​ 825 ​ 565 ​ 31 ​ 1,421 Totals ​ $ 12,809 ​ $ 2,592 ​ $ 658 ​ $ 16,059 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Collaboration and license revenue ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Collaboration and license revenue ​ $ 167 ​ $ 17 ​ $ — ​ $ 184 Totals $ 167 $ 17 $ — $ 184 ​ The Company’s contracts with customers may include promises to transfer multiple products and services to a customer. The Company combines 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. The aggregate amount of transaction price that is allocated to performance obligations that have not yet been satisfied or are partially satisfied as of December 31, 2020 is $6.0 million. Of the performance obligations not yet satisfied or are partially satisfied, $5.4 million is expected to be recognized as revenue in the next 12 months, with the remainder amounts Changes in deferred revenue from contracts with customers were as follows (in thousands): ​ ​ ​ ​ ​ Year Ended December 31, 2020 Balance at December 31, 2019 $ 5,163 Deferral of revenue ​ 6,955 Recognition of deferred revenue ​ (6,120) Balance at December 31, 2020 $ 5,998 ​ 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 changes in the balance of costs to obtain a contract are as follows (in thousands): ​ ​ ​ ​ ​ ​ Year Ended December 31, 2020 Balance at December 31, 2019 $ 335 Deferral of costs to obtain a contract ​ 506 Recognition of costs to obtain a contract ​ (593) Balance at December 31, 2020 $ 248 ​ 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 December 31, 2020 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 for the years ended December 31, 2020 and 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. ​ Grant revenue ​ The Company recognizes grant revenue as it performs services under the arrangement when the funding is committed. Revenues and related research and development expenses are presented gross in the consolidated statements of operations as the Company has determined it is the primary obligor under the arrangement relative to the research and development services. ​ Accounting for grants does not fall under ASC 606, as the grantor will not benefit directly from the Company’s expansion or product development. As there is no authoritative guidance under U.S. GAAP on accounting for government assistance to for-profit business entities, the Company has accounted for grants by analogy to International Accounting Standards (IAS) 20, Accounting for Government Grants and Disclosure of Government Assistance ​ Grants to the Company contain both monetary amounts granted related to assets and monetary amounts granted related to income, which are grants other than those related to assets. The grants related to assets are for the expansion and increase of manufacturing capacity. The grants related to income are for additional research and development, as well as other non-asset related scale up costs. ​ Under IAS 20, grants related to assets shall be presented in the consolidated balance sheets either by recognizing the grant as deferred income (which is recognized in the consolidated statements of operations on a systematic basis over the useful life of the asset), or by deducting the grant in calculating the carrying amount of the asset (which is recognized in the consolidated statements of operations over the life of the depreciable asset as a reduced depreciation expense). Both methods are acceptable under IAS 20. The Company has elected to record grants related to assets as a deduction in calculating the carrying value of the asset. ​ Under IAS 20, grants related to income are presented as part of the consolidated statements of operations, either separately or under a general heading. Both methods are acceptable under IAS 20. The Company has elected to record grants related to income separately on the consolidated statements of operations as grant revenue. The related expenses are recorded within operating expenses and not deducted. ​ On June 22, 2020, the Company entered into a workplan 1 award (WP1) with the National Institute of Health (NIH), under the Rapid Acceleration of Diagnostics (RADx) program to assess the feasibility of a novel SARS-CoV-2 antigen detection test using the Company’s Simoa technology. During the year ended December 31, 2020, the Company recognized $2.0 million of grant revenue and incurred $1.0 million in research and development expense related to WP1. WP1 is complete as of December 31, 2020. ​ On September 29, 2020, the Company entered into a workplan 2 award (WP2) with the NIH under its RADx program. WP2, which has a total award value of $18.2 million, accelerates the continued development, scale-up, and deployment of the novel SARS-CoV-2 antigen detection test using the Company’s Simoa technology. The contract provides funding to expand assay kit manufacturing capacity and commercial deployment readiness. Release of the $18.2 million of funding under WP2 is based on the achievement of certain milestones, and there is no assurance that the Company can meet all the milestones on a timely basis, if at all. If the Company does not meet all of the milestones, it will not be able access the full $18.2 million in funding under the contract. During the year ended December 31, 2020 the Company recognized $4.4 million in grant revenue and incurred $2.6 million in research and development expense related to WP2. ​ ​ ​ ​ ​ Total grant revenue from research and development activities $ 4,362 Total proceeds used for assets ​ 826 Total deferred proceeds for assets ​ 2,478 Total deferred grant revenue ​ 304 Total recognized $ 7,970 ​ ​ ​ Total recognized $ 7,970 Total amount accrued ​ (2,968) Total cash received $ 5,002 ​ ​ ​ Total proceeds received $ 5,002 Total proceeds reasonably assured ​ 13,198 Total WP2 grant amount $ 18,200 ​ Business combinations Under the acquisition method of accounting, the Company generally recognizes the tangible and identifiable intangible assets acquired and liabilities assumed based on their estimated fair values on the date of acquisition. The fair values recognized, 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 value of acquired tangible and intangible assets, net of liabilities recognized, 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. 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. Cost of revenue Cost of product revenue consists of raw materials, parts costs and associated freight, shipping and handling costs, contract manufacturer costs, personnel costs, yield loss, in-license payments and royalties, stock-based compensation, other direct costs and overhead. Cost of service and other revenue consists of personnel, facility costs associated with operating the Accelerator Labs on behalf of the customers, costs related to instrument maintenance and servicing equipment at customer sites, other direct and overhead. Cost of license revenue consists of license fees that are the direct results of cash payments received related to license agreements. Research and development expenses Research and development expenses, including personnel costs, allocated facility costs, lab supplies, outside services, contract laboratory costs are charged to research and development expense as incurred. The Company accounts for nonrefundable advance payments for goods and services that will be used in future research and development activities as expense when the service has been performed or when the goods have been received. Expenses incurred related to grant funded activities are recorded in research and development expense. Selling, general, and administrative expenses Selling, general, and administrative expenses are primarily composed of compensation and benefits associated with sales and marketing, finance, human resources, and other administrative personnel, outside marketing, advertising, allocated facilities costs, legal expenses, and other general and administrative costs. Net loss per share Basic net loss per common share attributable to common stockholders is calculated by dividing the loss attributable to common stockholders by the weighted-average number of common shares. For purposes of the diluted net loss per share calculations, unvested restricted common stock, common stock options, and warrants are considered to be potentially dilutive securities, but are excluded from the 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): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ ​ 2020 2019 2018 Unvested restricted common stock and restricted stock units ​ 518,387 409,929 361,468 Outstanding stock options 2,494,045 2,507,062 2,476,911 Outstanding common stock warrants 10,000 10,000 76,041 Total 3,022,432 2,926,991 2,914,420 ​ As of December 31, 2020, 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. Cash and cash equivalents Cash and cash equivalents consist of cash deposits and short-term, highly liquid investments that are readily convertible into cash, with original maturities of three months or less. Cash equivalents are carried at fair value based on quoted prices for identical assets. Cash and cash equivalents consist of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ ​ December 31, ​ 2020 2019 Cash ​ $ 19,535 ​ $ 6,406 Money market funds invested in U.S. Treasury obligations ​ 162,049 ​ 102,749 Total cash and cash equivalents ​ $ 181,584 ​ $ 109,155 ​ Restricted cash and deposits Restricted cash 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 December 31, 2020. As of both December 31, 2020 and 2019, the Company had $1.1 million in restricted cash and deposits related to amounts held for a line of credit, amounts held as a security deposit for the Company’s facility lease obligation, and a business registration application. As of both December 31, 2020 and 2019, $1.0 million of the $1.1 million was recorded on a separate line item as restricted cash. The remaining $0.1 million was included in noncurrent assets as of both December 31, 2020 and 2019. Accounts receivable and allowance for doubtful accounts The Company provides credit, in the normal course of business, to customers and does not require collateral. Accounts receivable consist of amounts due to the Company for sales to customers and are recorded net of an allowance for doubtful accounts. The Company reviews accounts receivable on a regular basis to determine if any receivable will potentially be uncollectable and to estimate the amount of allowance for doubtful accounts necessary. Once a receivable is deemed uncollectible, such balance is written off and charged against the allowance for doubtful accounts. The Company has not incurred material write offs in any of the periods presented. The Company’s allowance for doubtful accounts activity for the years ended December 31, 2020, 2019, and 2018 was as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2017 ​ $ — Additions ​ ​ 36 Deductions ​ ​ — December 31, 2018 ​ $ 36 Additions ​ ​ 160 Deductions ​ ​ (34) December 31, 2019 ​ $ 162 Additions ​ ​ 493 Deductions ​ ​ (285) December 31, 2020 ​ $ 370 ​ Inventory Inventory is stated at the lower of cost or market on a first-in, first-out (FIFO) basis. The Company analyzes its inventory levels on each reporting date and writes down inventory that is expected to expire prior to being sold and inventory in excess of expected sales requirements. In the event that the Company identifies these conditions exist in its inventory, the carrying value is reduced to its estimated net realizable value. Property and equipment Property and equipment, including leasehold improvements, are stated at cost and are depreciated, or amortized in the case of leasehold improvements, over their estimated useful lives using the straight-line method. Expenditures for maintenance and repairs are charged to expense as incurred, whereas major betterments are capitalized as additions to property and equipment. The Company reviews its property and equipment whenever events or changes in circumstances indicate that the carrying value of certain assets might not be recoverable and recognizes an impairment loss when it is probable that an asset’s realizable value is less than the carrying value. To date, no such impairment losses have been recorded. Depreciation is calculated based upon the following estimated useful lives of the assets: ​ ​ ​ ​ Laboratory and manufacturing equipment Five years Computers and software Three years Office furniture and equipment Seven years Leasehold improvements Shorter of the useful life of the asset or the remaining term of the lease ​ Software development costs The Company develops and modifies software related to the operation of the instrument. Software development costs are expensed as incurred until the point the Company establishes technological feasibility. Based on the Company’s product development process, technological feasibility is established upon the completion of a working model. The Company does not incur material costs between the completion of the working model and the point at which the product is ready for release. Therefore, software development costs are charged to the statement of operations as incurred as research and development expense. ​ Fair value of financial instruments ​ ASC Topic 820, Fair Value Measurement ​ 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. ​ To the extent that the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. ​ The carrying amount reflected on the balance sheets for cash and cash equivalents, accounts receivable, prepaid expenses and other current assets, accounts payable and accrued liabilities approximated their fair values, due to the short-term nature of these instruments. The carrying value of the long-term debt approximates its fair value as the debt arrangement is based on interest rates the Company believes it could obtain for borrowings with similar terms. The Company has an investment in the preferred stock of a privately held company which is recorded within other non-current assets on a cost basis. This cost method investment’s fair value has not been estimated as there are no identified events or changes in circumstances that would indicate a significant adverse effect on the fair value of the investment and to do so would be impractical. ​ Fair value measurements as of December 31, 2020 are as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Quoted prices ​ ​ ​ ​ Significant ​ ​ ​ ​ ​ in active ​ Significant other ​ unobservable ​ ​ ​ ​ ​ markets ​ observable ​ inputs Description Total (Level 1) inputs (Level 2) (Level 3) Financial assets ​ ​ ​ ​ ​ Cash equivalents $ 162,048 $ 162,048 ​ $ — $ — ​ ​ $ 162,048 ​ $ 162,048 ​ $ — ​ $ — ​ ​ Fair value measurements as of December 31, 2019 are as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Quoted prices ​ ​ ​ Significant ​ ​ ​ ​ ​ in active ​ Significant other ​ unobservable ​ ​ ​ ​ ​ markets ​ observable ​ inputs Description Total (Level 1) inputs (Level 2) (Level 3) Financial assets ​ ​ ​ ​ ​ Cash equivalents $ 102,749 $ 102,749 ​ $ — $ — ​ $ 102,749 $ 102,749 ​ $ — $ — ​ Warranties ​ The Company provides a one-year warranty and maintenance service related to its instruments and sells extended warranty contracts for additional periods. The Company defers revenue associated with these services and recognizes them on a pro-rata basis over the period of service. ​ Income taxes ​ The Company recognizes deferred tax assets and liabilities for the expected future tax consequences of events that have been recognized in the Company’s consolidated financial statements or tax returns. Under this method, deferred tax assets and liabilities are determined based on differences between the consolidated financial statement carrying amounts and the tax bases of the assets and liabilities using the enacted tax rates in effect in the years in which the differences are expected to reverse. A valuation allowance against deferred tax assets is recorded if, based on the weight of the available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. ​ The Company accounts for uncertain tax positions in accordance with the provisions of ASC 740 Income Taxes ​ Credit, product and supplier concentrations and off-balance-sheet risk The Company has no significant off-balance-sheet risk, such as foreign exchange contracts, option contracts, or other hedging arrangements. Financial instruments that potentially expose the Company to concentrations of credit risk primarily consist of cash and cash equivalents and a cost method investment. The Company places its cash and cash equivalents principally in depository accounts with a bank. The Company is also subject to supply chain risks related to the outsourcing of the manufacturing of its instruments. Although there are a limited number of manufacturers for instruments of this type, the Company believes that other suppliers could provide similar products on comparable terms. A change in suppliers, however, could cause a delay in manufacturing and a possible loss of sales, which would adversely affect operating results. In addition to outsourcing the manufacturing of its instruments, the Company also purchases antibodies through a number of different suppliers. Although a disruption in service from any one of its antibody suppliers is possible, the Company believes that it would be able to find an adequate supply from alternative suppliers. Customers outside the United States represented 29% and 50% of the Company’s gross trade accounts receivable balance as of December 31, 2020 and 2019, respectively. As of December 31, 2020, one customer represented 19% of the Company’s aggregate accounts receivable. As of December 31, 2019, and 2018, no single customer represented 10% of the Company’s aggregate accounts receivable. During the year ended December 31, 2020 one customer represented 13% of the Company’s total revenue. For the years ended December 31, 2019 and 2018, no single customer represented 10% of the Company’s total revenue. Stock-based compensation ​ The Company accounts for stock-based compensation awards in accordance with ASC 718, Compensation—Stock Compensation Prior to the adoption of Accounting Standards Update (ASU) No. 2018-07, Compensation - Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting ​ Effective January 1, 2017, the Company ceased utilizing an estimated forfeiture rate and began recognizing forfeitures as they occur. The Company estimates the grant date fair value, and the resulting stock-based compensation expense, using the Black-Scholes option-pricing model. The grant date fair value of the stock-based awards is generally recognized on a straight-line basis over the requisite service period, which is generally the vesting period of the respective awards. The fair value of stock options granted to employees and non-employees is estimated on the grant date using the Black-Scholes option-pricing model, based on the assumptions noted in the following table: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ 2020 ​ 2019 ​ 2018 Risk-free interest rate 0.4% - 1.7% ​ 1.4% - 2.6% ​ 2.6% - 3.0% Expected dividend yield None ​ None ​ None Expected term (in years) 6 ​ 6.0 ​ 5.9 Expected volatility 43.9% - 49.2% ​ 33.5% - 39.7% ​ 32.4% - 36.8% ​ Using the Black-Scholes option-pricing model, the weighted-average grant date fair value of options granted for the years ended December 31, 2020, 2019, and 2018 was $12.66, $9.09, and $7.19 per share, respectively. Expected volatility was calculated based a proportional weighting of reported volatility data for a representative group of guideline publicly traded companies for which historical information was available, as well as the Company’s sto

Inventory

Inventory	12 Months Ended
	Dec. 31, 2020
Inventory
Inventory	3. Inventory Inventory consists of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2020 2019 Raw materials ​ $ 5,265 ​ $ 4,717 Work in process ​ 3,306 ​ 2,573 Finished goods ​ 6,285 ​ 3,173 Total ​ $ 14,856 ​ $ 10,463 ​ Inventory comprises commercial instruments, assays, and the materials required to manufacture assays.

Property and equipment

Property and equipment	12 Months Ended
	Dec. 31, 2020
Property and equipment
Property and equipment	4. Property and equipment Property and equipment consists of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ ​ December 31, ​ 2020 2019 Laboratory and manufacturing equipment ​ $ 8,523 ​ $ 5,391 Office furniture and equipment ​ 1,556 ​ 1,403 Computers and software ​ 1,504 ​ 1,103 Leasehold improvements ​ 8,765 ​ 8,489 Total ​ $ 20,348 ​ $ 16,386 ​ ​ ​ ​ ​ Less: accumulated depreciation ​ (6,436) ​ (4,339) Total ​ $ 13,912 ​ $ 12,047 ​ The Company incurred depreciation expense of $2.2 million and $1.6 million for the years ended December 31, 2020 and 2019, respectively. The Company has instruments included in laboratory and manufacturing equipment, which are used internally by the Company. As of December 31, 2020, the laboratory and manufacturing equipment balance includes $3.4 million of cost and $1.8 million of accumulated depreciation related to these instruments. As of December 31, 2019, the laboratory and manufacturing equipment balance includes $2.8 million of cost and $1.2 million of accumulated depreciation related to these instruments.

Other accrued expenses

Other accrued expenses	12 Months Ended
	Dec. 31, 2020
Other accrued expenses
Other accrued expenses	5. Other accrued expenses Other accrued expenses consist of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ December 31, ​ 2020 2019 Accrued inventory purchases ​ $ 527 ​ $ 459 Accrued royalties ​ 1,845 ​ 476 Accrued professional services ​ 797 ​ 655 Accrued development costs ​ 323 ​ 151 Accrued other ​ 1,353 ​ 757 Total accrued expenses ​ $ 4,845 ​ $ 2,498 ​ ​ Other non-current liabilities consist of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ December 31, ​ ​ 2020 ​ 2019 Leasehold obligation incentive ​ $ — ​ $ 7,572 Deferred rent ​ ​ — ​ ​ 3,009 Deferred tax liabilities ​ ​ 2,649 ​ ​ 2,825 Other ​ ​ — ​ ​ 1 Total other non-current liabilities ​ $ 2,649 ​ $ 13,407 ​

Income taxes

Income taxes	12 Months Ended
	Dec. 31, 2020
Income taxes
Income taxes	6. Income taxes ​ The following table presents the components of loss before income taxes (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ ​ 2020 ​ 2019 2018 United States ​ $ (29,896) ​ $ (40,010) ​ $ (31,436) Foreign ​ (2,010) ​ (973) ​ (75) ​ ​ $ (31,906) ​ $ (40,983) ​ $ (31,511) ​ The following table summarizes income tax benefit (provision) (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ December 31, ​ 2020 2019 2018 Current: ​ ​ ​ ​ ​ ​ ​ ​ ​ United States ​ ​ ​ ​ ​ ​ ​ ​ ​ Federal $ — $ — $ — State ​ ​ (13) ​ ​ (20) ​ ​ (18) Foreign ​ ​ (102) ​ ​ (93) ​ ​ — Total current income tax provision ​ ​ (115) ​ ​ (113) ​ ​ (18) Deferred ​ ​ ​ ​ ​ ​ ​ ​ ​ United States ​ ​ ​ ​ ​ ​ ​ ​ ​ Federal ​ ​ (8) ​ ​ (3) ​ ​ (2) State ​ ​ (3) ​ ​ (1) ​ ​ (5) Foreign ​ ​ 502 ​ ​ 304 ​ ​ — Total deferred income tax benefit (provision) ​ ​ 491 ​ ​ 300 ​ ​ (7) Total income tax benefit (provision) $ 376 ​ $ 187 ​ $ (25) ​ During the years ended December 31, 2020, 2019, and 2018, the Company recorded an income tax benefit (provision) of $0.4 million, $0.2 million, and $(0.0) million, respectively. A reconciliation of the federal statutory income tax rate to the effective tax rate is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ ​ 2020 2019 2018 Federal statutory income tax rate 21.0 % 21.0 % 21.0 % Foreign tax rate differential 0.3 % — % — % State taxes, net of federal benefit 2.5 % 3.2 % 6.0 % Tax credits 1.6 % 2.3 % 2.7 % Share-based compensation 5.2 % 2.3 % 1.1 % Permanent items (0.4) % (0.9) % (1.2) % Deferred tax rate change ​ 0.3 % (1.4) % — % Change in valuation allowance (29.7) % (24.6) % (29.9) % Other ​ 0.4 % (1.4) % 0.2 % Effective income tax rate 1.2 % 0.5 % (0.1) % ​ The effective tax rate of 1.2% differs from the U.S. Federal statutory rate of 21.0% primarily as a result of the valuation allowance maintained against the Company’s net deferred tax assets. During 2018, the Company acquired Aushon. The Company analyzed the transaction from an income tax perspective and adjusted the deferred tax assets and liabilities related to the Aushon acquisition. Of the total goodwill recorded, approximately $0.3 million is amortizable related to historical tax basis that Aushon had related to a prior acquisition. During 2019, the Company acquired Uman, a Swedish entity. The Company analyzed the transaction from an income tax perspective and found that there was no tax deductible goodwill or other identifiable intangible assets related to the transaction. ​ Deferred tax assets and liabilities reflect the net tax effects of temporary differences between the carrying amount of assets and liabilities for financial reporting and the amounts used for income tax purposes. Significant components of the Company’s deferred tax assets and liabilities were as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2020 2019 Deferred tax assets: ​ ​ Net operating loss carryforwards ​ $ 50,233 ​ $ 43,814 Tax credits ​ 5,101 ​ 5,518 Deferred revenue ​ ​ 2,167 ​ ​ 1,247 Amortization ​ ​ 1,054 ​ ​ 928 Stock-based compensation ​ 1,956 ​ 973 Deferred rent ​ ​ — ​ ​ 727 Lease incentive obligation ​ ​ — ​ ​ 1,828 Lease liability ​ ​ 5,703 ​ ​ — Other deferred tax assets ​ ​ 2,533 ​ ​ 1,325 Total deferred tax assets ​ 68,747 ​ 56,360 Less: valuation allowances ​ ​ (63,609) ​ ​ (54,137) Net deferred tax assets ​ ​ 5,138 ​ ​ 2,223 Deferred tax liabilities: ​ ​ ​ ​ ​ ​ Right-of-Use Assets ​ ​ (2,957) ​ ​ — Depreciation ​ ​ (1,775) ​ ​ (1,769) Amortization acquired intangibles ​ ​ (2,880) ​ ​ (3,031) Inventory ​ ​ (64) ​ ​ (212) Goodwill ​ ​ (49) ​ ​ (31) Other deferred tax liabilities ​ ​ (61) ​ ​ (5) Net deferred tax liabilities ​ $ (2,648) ​ $ (2,825) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 Balance, beginning of year ​ $ 54,137 ​ $ 44,033 Change in valuation allowance ​ ​ 9,472 ​ ​ 10,104 Balance, end of year ​ $ 63,609 ​ $ 54,137 ​ The valuation allowance increased by $9.5 million during the year ended December 31, 2020, primarily as a result of the U.S. operating losses incurred, and research and development tax credit carryforwards generated during the year. ​ In determining the need for a valuation allowance, the Company has given consideration to the cumulative book income and loss positions of each of its entities as well as its worldwide cumulative book loss position. The Company has assessed, on a jurisdictional basis, the available means of recovering deferred tax assets, including the ability to carryback net operating losses (NOLs), the existence of reversing taxable temporary differences, the availability of tax planning strategies, and forecasted future taxable income. At December 31, 2020, the Company maintains a full valuation allowance against its worldwide net deferred tax assets. As of December 31, 2020, the Company had U.S. federal NOLs of approximately $199.3 million. U.S. federal NOLs generated through December 31, 2017 of approximately $108.5 million expire at various dates through 2037, and U.S. federal NOLs generated in the tax years beginning after December 31, 2017 of approximately $90.8 million do not expire. As of December 31, 2020, the Company had $133.7 million of state NOLs, some of which are indefinite lived and some that expire at various dates through 2040. As of December 31 2020, the Company had U.S. federal tax credit carryforwards of approximately $4.5 million that expire at various dates through 2040. As of December 31, 2020, the Company had U.S. state tax credit carryforwards of approximately $0.8 million that expire at various dates through 2040. Under Sections 382 and 383 of the U.S. Internal Revenue Code, if a corporation undergoes an ownership change, the corporation’s ability to use its pre-change NOLs and other pre-change tax attributes, such as research tax credits, to offset its post-change income and taxes may be limited. In general, an ownership change generally occurs if there is a cumulative change in its ownership by 5% stockholders that exceeds 50 percentage points over a rolling three-year period. Similar rules may apply under U.S. state tax laws. Under the TCJA, the use of federal NOLs arising in taxable years beginning after December 31, 2017 is limited to 80% of current year taxable income and NOLs arising in taxable years ending after December 31, 2017 may not be carried back (though any such NOLs may be carried forward indefinitely). ​ The Company may have experienced an ownership change in the past and may experience ownership changes in the future as a result of future transactions in its share capital, some of which may be outside of the control of the Company. As a result, if the Company earns net taxable income, its ability to use its pre-change NOLs, or other pre-change tax attributes, to offset U.S. federal and state taxable income and taxes may be subject to significant limitations. ​ The Coronavirus Aid, Relief and Economic Security Act (the CARES Act) was enacted in the United States on March 27, 2020. The CARES Act is an emergency economic stimulus package that includes spending and tax breaks to strengthen the United States economy and fund a nationwide effort to curtail the effect of COVID-19. While the CARES Act provides extensive tax changes in response to the COVID-19 pandemic, the provisions do not have a significant impact on the Company’s financial results. ​ The Company accounts for uncertain tax positions using a more likely than not threshold for recognizing uncertain tax positions. The evaluation of uncertain tax positions is based on factors that include, but are not limited to, changes in tax law, the measurement of tax positions taken or expected to be taken in tax returns, the effective settlement of matters subject to audit, new audit activity and changes in facts or circumstances related to a tax position. The Company evaluates uncertain tax positions on an ongoing basis and adjusts the level of the liability to reflect any subsequent changes in the relevant facts surrounding the uncertain positions. The Company accounts for interest and penalties related to uncertain tax positions as a component of its benefit (provision) for income taxes. For the years ended December 31, 2020, 2019, and 2018, the Company had no tax reserves accrued for uncertain tax positions and there were no accrued interest or penalties in the consolidated statements of operations. ​ The Company is subject to taxation in the United States as well as the Netherlands, Sweden, and China. At December 31, 2020, the Company is generally no longer subject to examination by taxing authorities in the United States for years prior to 2017. However, NOLs and credits in the United States may be subject to adjustments by taxing authorities in future years in which they are utilized. The Company’s foreign subsidiaries remain open to examination by taxing authorities from 2015 onward. As of December 31, 2020, the Company’s foreign subsidiaries had immaterial undistributed earnings and the tax payable on the earnings that are indefinitely reinvested would be immaterial.

Common Stock, warrants, stock-b

Common Stock, warrants, stock-based compensation, stock options, restricted stock and restricted stock units	12 Months Ended
	Dec. 31, 2020
Common Stock, warrants, stock-based compensation, stock options, restricted stock and restricted stock units
Common Stock, warrants, stock-based compensation, stock options, restricted stock and restricted stock units	7. Common Stock, warrants, stock-based compensation, stock options, restricted stock and restricted stock units Common stock reserved The Company reserved the following shares of common stock, on a common stock equivalent basis, for the exercise of warrants, the exercise of common stock options, and the vesting of restricted common stock. ​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ 2020 2019 Common stock warrants 10,000 10,000 Common stock options and unvested restricted common stock 3,012,432 2,916,991 Shares reserved for future awards under compensation plans 1,559,108 882,715 ​ 4,581,540 3,809,706 ​ Warrants The following table summarizes the Company’s outstanding warrants as of December 31, 2020, and 2019: ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ Issued and ​ Average ​ exercisable Exercise Price As of December 31, 2019 10,000 ​ $ 21.00 Issued — ​ — Exercised — ​ — Cancelled — ​ ​ — As of December 31, 2020 10,000 ​ $ 21.00 ​ The Company has an agreement with a vendor (Note 9) where the Company could be obligated to issue warrants to purchase an additional 93,341 shares of common stock to the vendor if the contract is terminated prior to a minimum purchase commitment being met. No shares have been reserved related to these potential obligations to issue warrants in the future. On January 30, 2018, the Company issued a warrant to purchase 10,000 of common stock to a consultation company for services rendered. On July 2, 2019, 66,041 warrants were exercised by a holder on a net, non-cash, basis. Per terms of the warrant agreement, the Company issued 45,690 shares of common stock after giving effect to the holder’s net exercise. Stock-based compensation Share-based compensation expense for all stock awards consists of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ ​ ​ 2020 2019 2018 Cost of product revenue ​ ​ $ 189 ​ $ 86 ​ $ 55 Cost of service and other revenue ​ ​ 311 ​ 238 ​ 173 Research and development ​ ​ 1,129 ​ 718 ​ 513 Selling, general, and administrative ​ ​ 8,470 ​ 5,346 ​ 4,143 Total ​ ​ $ 10,099 ​ $ 6,388 ​ $ 4,884 ​ In June 2007, the Company adopted the 2007 Stock Option and Grant Plan (the 2007 Plan), under which it could grant incentive stock options, non-qualified options, restricted stock, and stock grants. In connection with the completion of the IPO, the Company terminated the 2007 Plan. As of December 31, 2020, 926,615 shares were outstanding and no shares were available for future grant under 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 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 became effective. As of December 31, 2020 and 2019, there were shares available for grant under the 2017 Plan of 710,839 and 270,143, respectively. In addition, 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. On January 1, 2021, the number of shares of common stock available for issuance under the 2017 plan was automatically increased by 1,273,501 shares. In December 2017, the Company adopted the 2017 Employee Stock Purchase Plan (the 2017 ESPP). As December 31, 2019, the 2017 ESPP allowed for the issuance of up to 612,572 shares of common stock. As of December 31, 2020, 848,269 shares were available for grant under the 2017 ESPP. In addition, 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 318,375 shares on January 1, 2021 due to this provision. The 2017 ESPP provides for six-month option periods commencing on March 1 and ending August 31 and commencing September 1 and ending February 28 of each calendar year. The first offering under the 2017 ESPP began on September 1, 2018. Stock options Under the 2007 and 2017 Plans, 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 were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted-average ​ Remaining contractual ​ Aggregate intrinsic value ​ Options exercise price life (in years) (in thousands) Outstanding at December 31, 2019 2,507,062 $ 14.41 ​ 7.58 ​ $ 24,870 Granted 550,290 ​ $ 28.39 ​ ​ ​ ​ ​ Exercised (407,687) ​ $ 9.85 ​ ​ ​ ​ ​ Cancelled (155,620) ​ $ 22.58 ​ ​ ​ ​ ​ Outstanding at December 31, 2020 2,494,045 ​ $ 17.73 ​ 7.27 ​ $ 71,760 Vested and expected to vest at December 31, 2020 2,494,045 ​ $ 17.73 ​ 7.27 ​ $ 71,760 Exercisable at December 31, 2020 ​ 1,514,576 ​ $ 12.54 ​ 6.42 ​ $ 51,430 ​ Using the Black-Scholes option pricing model, the weighted-average fair value of options granted to employees and directors during the years ended December 31, 2020, 2019, and 2018 was $12.64, $9.09, and $7.19 per share, respectively. The expense related to stock options granted to employees was $5.4 million, $3.7 million, and $2.7 million for the years ended December 31, 2020, 2019, and 2018, respectively. The intrinsic value of stock options exercised was $10.4 million, $6.9 million, and $5.3 million, for the years ended December 31, 2020, 2019, and 2018, respectively. On December 7, 2020, the Company entered into an agreement with a non-employee director related to the extension of the exercise period, resulting in $0.5 million of stock-based compensation expense recorded in selling, general and administrative expense during the year ended December 31, 2020. At December 31, 2020, there was $9.3 million of total unrecognized compensation cost related to unvested stock options, which is expected to be recognized over the remaining weighted-average vesting period of 7.3 years. Restricted stock awards 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 during the years ended December 31, 2020, 2019, or 2018. As of December 31, 2020, the Company had 39,806 shares of unvested restricted common stock with a weighted average grant date fair value of $3.12 per share. ​ The expense related to restricted stock awards granted to employees and non-employees was $0.0 million, $0.0 million, and $0.4 million for the years ended December 31, 2020, 2019, and 2018, respectively. At December 31, 2020, there was no unrecognized compensation cost related to unvested restricted stock. The aggregate fair value of restricted stock awards that vested during the years ended December 31, 2020, 2019, and 2018, based on estimated fair values of the stock underlying the restricted stock awards on the day of vesting, was $0.0 million, $0.0 million and $2.4 million, respectively. Restricted stock units Restricted stock units (RSUs) represent the right to receive shares of common stock upon meeting specified vesting requirements. In the fiscal year ended December 31, 2020, the Company issued 334,665 RSUs to employees of the Company under the 2017 Plan. Under the terms of the agreements, 268,694 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 vested on December 31, 2020, 40,045 of the RSUs vest equally over three years on the anniversary of the vesting start date, 8,576 vested immediately upon grant, and 1,460 RSUs vest on May 31, 2021. A summary of RSU activity is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted-average ​ ​ ​ ​ grant date ​ ​ ​ ​ fair value ​ Shares per share Unvested RSUs as of December 31, 2019 370,123 $ 20.48 Granted 334,665 ​ $ 31.99 Vested (182,036) ​ $ 20.13 Cancelled (44,171) ​ $ 26.79 Unvested RSUs as of December 31, 2020 478,581 ​ $ 28.08 ​ The expense related to RSU awards granted to employees and non-employee directors was $4.2 million for the fiscal year ended December 31, 2020. At December 31, 2020, there was $12.0 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 2.8 years.

Leases

Leases	12 Months Ended
	Dec. 31, 2020
Leases
Leases	8. Leases ​ The Company is a lessee under leases of offices, lab spaces, and certain office equipment. Some of the Company’s leases include options to extend the lease, and these options are included in the lease term to the extent they are reasonably certain to be exercised. ​ 900 Middlesex Turnpike Lease ​ The Company’s primary lease is the 900 Middlesex Turnpike Lease. On October 2, 2018, the Company entered into a 137-month operating lease for the Company’s new headquarters in Billerica, Massachusetts. The lease is for approximately 92,000 square feet of office and laboratory space and commenced on April 1, 2019. 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, which will be subsequently reduced throughout the lease term. Pursuant to a work letter entered into in connection with the 900 Middlesex Turnpike Lease, the landlord contributed an aggregate of $8.2 million toward the cost of construction and tenant improvements for the building. Under the lease, the Company has the option to extend the lease for two successive five-year terms, and the renewal options are not reasonably certain to be exercised. ​ In applying the ASC 842 transition guidance, the 900 Middlesex Turnpike Lease remained classified as an operating lease and the Company recorded ROU assets of $12.2 million and lease liability of $22.7 million on the effective date. The difference between the ROU and the lease liability was driven by the Company derecognizing deferred rent of $3.0 million and the lease obligation incentive of $7.6 million. The Company is recognizing rent expense on a straight-line basis throughout the remaining term of the leases. ​ 48 Tvistevägen ​ The Company has multiple leases at 48 Tvistevägen Umeå, Sweden for laboratory spaces, manufacturing spaces, and office space (the Uman leases). All of these Uman leases have been assessed as operating leases. ​ In applying the ASC 842 transition guidance, the Uman leases remained classified as operating leases and the Company recorded ROU assets of less than $0.1 million and lease liability of less than $0.1 million on the effective date. The Company is recognizing rent expense on a straight-line basis throughout the remaining term of the leases. ​ Summary of all lease costs recognized under ASC 842 ​ The following table contains a summary of the lease costs recognized under ASC 842 and other information pertaining to the Company’s operating leases for the year ended December 31, 2020: ​ ​ ​ ​ ​ ​ Operating leases (in thousands) ​ ​ For the year ended December 31, 2020 Lease Costs (1) ​ ​ ​ ​ Operating lease costs ​ ​ $ 2,663 Total lease cost ​ ​ $ 2,663 ​ ​ ​ ​ ​ Other information ​ ​ ​ ​ Operating cash flows used for operating leases ​ ​ $ 2,108 Weighted average remaining lease term (years) ​ ​ ​ 9.8 Weighted average discount rate ​ ​ ​ 9.73% ​ (1) Short-term lease costs and variable lease costs incurred by the Company for the year ended December 31, 2020 were considered immaterial. ​ Rent expense is calculated on a straight-line basis over the term of the lease. Rent expense recognized under all leases was $4.8 million, $3.3 million, and $1.6 million for the years ended December 31, 2020, 2019, and 2018, respectively. Note that the Company adopted ASC 842 effective January 1, 2020 using the required modified retrospective approach and utilizing the effective date as its date of initial application. Therefore, amounts disclosed pertaining to the years ended December 31, 2019 and 2018 are presented under previous accounting guidance and are therefore not comparable to the amounts recorded in the current period under ASC 842. ​ ​ ​ As of December 31, 2020, future minimum commitments under ASC 842 under the Company’s operating leases were as follows: ​ ​ ​ ​ ​ Maturity of lease liabilities (in thousands) ​ As of December 31, 2020 2021 ​ $ 3,388 2022 ​ ​ 3,466 2023 ​ ​ 3,515 2024 ​ ​ 3,577 2025 and thereafter ​ ​ 22,203 Total lease payments ​ $ 36,149 Less: imputed interest ​ ​ 13,024 Total operating lease liabilities ​ $ 23,125 ​

Commitments and contingencies

Commitments and contingencies	12 Months Ended
	Dec. 31, 2020
Commitments and contingencies
Commitments and contingencies	9. Commitments and contingencies License agreements 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 Tuft’s 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 years ended December 31, 2020, 2019, and 2018, the Company recorded royalty expense of $1.1 million, $1.0 million and $0.7 million, respectively, in cost of product revenue on the consolidated statements of operations. During the year ended December 31, 2020, the Company incurred $1.0 million in cost of collaboration and license revenue owed to Tufts related to sublicensing certain technology and intellectual property to Abbott Laboratories (Abbott) (see Note 13). Other licenses 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-sublicenseable 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 thousand. In September 2019, all remaining patents related to the intellectual property expired and the license agreement terminated. As this agreement was terminated in 2019, the Company recorded no royalty expense during the year ended December 31, 2020. During the 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 $11.7 million is payable to STRATEC Biomedical 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 ended December 31, 2018. Substantive efforts related to these additional development activities started in the first quarter of 2019 and were completed in the third quarter of 2019. The Company’s supply agreement with STRATEC Biomedical required 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 December 31, 2020 the Company has satisfied its required minimum purchase amount per the supply agreement. 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 December 31, 2020 and December 31, 2019 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

Notes payable	12 Months Ended
	Dec. 31, 2020
Notes payable
Notes payable	10. Notes payable Loan agreement On April 14, 2014, the Company executed a Loan Agreement with a lender, as subsequently amended, most recently in April 2019. As of December 31, 2020 and 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%. 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. Amendment 5 to loan agreement In August 2018, the Company signed Amendment 5 to the Loan Agreement (Amendment 5). Amendment 5 instituted a 2018 End of Term Charge of $0.08 million. Additionally, the Term Loan Maturity Date extended until March 1, 2020. Amendment 5 additionally, changed the due date of the End of Term Charge to, the earlier of (i) the Term Loan Maturity Date, (ii) the date that Borrower prepays the outstanding Secured Obligations or (iii) the date that the Secured Obligations become due and payable. The Company incurred a cost of $0.05 million in relation to the execution of Amendment 5. In connection with the extension of the due date of the Loan, the deferral of principal payments (Amendment 3) was further deferred until the new Term Loan Maturity Date. On March 2, 2020, the Company paid $0.1 million in end of term fees related to Amendment 5 of the loan agreement. Amendment 6 to loan agreement In October 2018, the Company signed Amendment 6 to the Loan agreement, which amended the Loan Agreement’s collateral clause to exclude the $1.0 million certificate of deposit associated with the lease on the Company’s new headquarters in Billerica, MA. Amendment 7 to loan agreement 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 Charge” 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 four equal installments starting July 1, 2021 with the final principal payment to be made on October 1, 2021. As of December 31, 2020, debt payment obligations due based on principal payments are as follows (in thousands): ​ ​ ​ ​ ​ 2021 ​ $ 7,688 Total ​ $ 7,688 ​ Non-cash interest expense related to debt discount amortization and accretion of end of term fees was $0.1 million, $0.1 million, and $0.2 million for the year ended December 31, 2020, 2019, and 2018, respectively. The Company assessed all terms and features of the Loan Agreement and the subsequent amendments in order to identify any potential embedded features that would require bifurcation. As part of this analysis, the Company assessed the economic characteristics and risks of the debt. The Company determined that all features of the Loan Agreement and the subsequent amendments are either clearly and closely associated with a debt host or have a de minimis fair value and, as such, do not require separate accounting as a derivative liability. The Company assessed each amendment under ASC 470-50 Debt – Modifications and Extinguishments The Loan Agreement and the subsequent amendments contain negative covenants restricting the Company’s activities, including limitations on dispositions, mergers or acquisitions, incurring indebtedness or liens, paying dividends or making investments and certain other business transactions. There are no financial covenants associated with the Loan Agreement and the subsequent amendments. The obligations under the Loan Agreement and subsequent amendments are subject to acceleration upon the occurrence of specified events of default, including a material adverse change in the Company’s business, operations or financial or other condition. The Company has determined that the risk of subjective acceleration under the material adverse events clause is not probable and therefore has classified the outstanding principal in current and long-term liabilities based on scheduled principal payments.

At-the-market offering

At-the-market offering	12 Months Ended
	Dec. 31, 2020
At-the-market offering
At-the-market offering	11. “At-the-market offering” On March 19, 2019, the Company entered into the Sales Agreement with Cowen with respect to an “at-the-market” offering program under which the Company could offer and sell, from time to time at its sole discretion, shares of its common stock, having an aggregate offering price of up to $50.0 million through Cowen as its sales agent. On June 5, 2019, the Company issued approximately 2.2 million shares of common stock at an average stock price of $22.73 per share pursuant to the terms of the Sales Agreement. The “at-the-market” offering resulted in gross proceeds of $49.7 million. The Company incurred $1.7 million in issuance costs associated with the “at-the-market” offering, resulting in net proceeds to the Company of $48.0 million. On August 6, 2020, the Company delivered written notice to Cowen to terminate the Sales Agreement, which termination the parties agreed to make immediately effective.

Underwritten public offerings

Underwritten public offerings	12 Months Ended
	Dec. 31, 2020
Underwritten public offerings
Underwritten public offerings	12. Underwritten public offerings On August 8, 2019, the Company entered into an underwriting agreement with J.P. Morgan Securities LLC and SVB Leerink LLC, as representatives of the several underwriters, relating to an underwritten public offering of approximately 2.7 million shares of the Company’s common stock, par value $0.001 per share. The underwritten public offering resulted in gross proceeds of $69.0 million. The Company incurred $4.5 million in issuance costs associated with the underwritten public offering, resulting in net proceeds to the Company of $64.5 million. On August 6, 2020, the Company entered into an underwriting agreement with Leerink and Cowen, as representatives of the several underwriters, relating to an underwritten public offering of approximately 3.0 million shares of the Company’s common stock, par value $0.001 per share. The underwritten public offering resulted in gross proceeds of $97.6 million. The Company incurred $6.2 million in issuance costs associated with the underwritten public offering, resulting in net proceeds to the Company of $91.4 million.

Collaboration and license arran

Collaboration and license arrangements	12 Months Ended
	Dec. 31, 2020
Collaboration and license arrangements
Collaboration and license arrangements	13. Collaboration and license arrangements ​ The Company has entered into certain licenses with other companies for use of the Company’s technology. These licenses have royalty components which the Company earns and recognizes as collaboration and license revenue throughout the year. The Company recognized revenue of less than $0.1 million for the years ended December 31, 2020 and 2019 associated with these licenses. ​ During the year ended December 31, 2020, the Company recognized $1.2 million of previously deferred revenue as a result of entering into a license agreement with a diagnostics company. As of December 31, 2020 and 2019, the Company had $0.5 million and $1.7 million, respectively, of deferred revenue related to ongoing negotiations with a diagnostics company. ​ Abbott Laboratories ​ On September 29, 2020, the Company entered into a Non-Exclusive License Agreement (the Abbott License Agreement) with Abbott. Pursuant to the terms of the Abbott License Agreement, the Company granted Abbott a non-exclusive, worldwide, royalty-bearing license, without the right to sublicense, under the Company’s bead-based single molecule detection patents (Licensed Patents) in the field of in vitro ​ The Abbott License Agreement includes customary representations and warranties, covenants and indemnification obligations for a transaction of this nature. The Abbot License Agreement became effective upon signing and will continue until expiration of the last-to-expire Licensed Patent, or the agreement is earlier terminated. Under the terms of the Abbott License Agreement, the Company and Abbott each have the right to terminate the agreement for uncured material breach by, or insolvency of, the other party. Abbott may also terminate the Abbott License Agreement at any time without cause upon 60 days’ notice. ​ During the year ended December 31, 2020, the Company recognized $10.0 million within collaboration and license revenue related to the initial license fee under the Abbott License Agreement. ​

Employee benefit plans

Employee benefit plans	12 Months Ended
	Dec. 31, 2020
Employee benefit plans
Employee benefit plans	14. Employee benefit plans The Company sponsors a 401(k) savings plan for employees. The Company may make discretionary contributions for each 401(k) plan year. During the years ended December 31, 2020, 2019, and 2018, the Company made contributions of $0.7 million, $0.5 million, and $0.1 million, respectively.

Business combinations

Business combinations	12 Months Ended
	Dec. 31, 2020
Business combinations
Business combinations	15. Business combinations Aushon BioSystems,Inc. On January 30, 2018, the Company completed the acquisition of Aushon pursuant to an Agreement and Plan of Merger dated January 30, 2018. The Company acquired Aushon to complement its existing product line, improve its existing research and development capabilities in assay development and software engineering, and expand its customer base. The acquisition of Aushon was accounted for as a business combination and the Company has recorded the assets acquired and liabilities assumed at their respective fair values as of the acquisition date. The following table presents acquisition accounting as of January 30, 2018 (in thousands): ​ ​ ​ ​ Fair value of consideration transferred: ​ Cash ​ $ 3,200 Obligation to issue cash ​ 800 Total acquisition consideration ​ $ 4,000 ​ ​ ​ ​ Fair value of assets acquired and liabilities assumed: ​ Cash and cash equivalents ​ $ 199 Accounts receivable ​ 210 Inventory ​ 828 Prepaid expenses ​ 71 Property and equipment and other non-current assets ​ 180 Intangible Assets ​ 2,950 Goodwill ​ 1,308 Total assets acquired ​ 5,746 Contractual obligations ​ (1,155) Accounts payable and accrued liabilities ​ (591) Net assets acquired ​ $ 4,000 ​ The intangible assets identified in the purchase price allocation discussed above include developed technology, tradenames and customer relationships. Tradenames are amortized over the useful life on a straight-line basis, while developed technology and customer relationships are amortized over their respective useful lives on an accelerated basis reflecting the period of expected derived benefits of the underlying assets. Developed technology consists of products that have reached technological feasibility and trade names represent acquired company and product names. To value the developed technology and trade name assets, the Company utilized a relief from royalty method. Under the methodology, fair value is calculated as the discounted cash flow savings accruing to the owner for not having to pay the royalty. Key assumptions included expected revenue attributable to the assets, royalty rates, discount rate and estimated asset lives. Customer relationships represent the underlying relationships with certain customers to provide ongoing services and continued product sale opportunities. The Company utilized excess earnings methodology to derive the fair value of the customer relationships. Key assumptions included expected attrition of customer's rates, operating income margins and discount rate. The Company used a risk-adjusted discount rate of 14.4% in determining the fair value of the intangible assets. The goodwill recorded as a result of the acquisition of Aushon represents the strategic benefits of growing the Company's product portfolio and the expected revenue growth from increased market penetration from future products and customers. None of the goodwill recorded is tax deductible for income tax purposes. The Company incurred a total of $0.1 million in transaction costs in connection with the transaction, which were included in selling, general and administrative expense within the consolidated statement of operations for the year ended December 31, 2018. UmanDiagnostics AB On August 1, 2019, the Company completed its acquisition of Uman for an aggregate purchase price of $21.2 million, comprised of (i) $15.7 million in cash plus (ii) 191,152 shares of common stock (representing $5.5 million based on the closing prices of the Company’s common stock on the Nasdaq Global Market on July 1, 2019 and August 1, 2019, the dates of issuance). The acquisition of Uman closed with respect to 95% of the outstanding shares of capital stock of Uman on July 1, 2019 and with respect to the remaining 5% of the outstanding shares of capital stock of Uman on August 1, 2019. Uman supplies Nf-L antibodies and ELISA kits, which are widely recognized by researchers and biopharmaceutical and diagnostics companies world-wide as the premier solution for the detection of Nf-L to advance the development of therapeutics and diagnostics for neurodegenerative conditions. With the acquisition of Uman, the Company has secured a long-term source of supply for a critical technology. This acquisition was considered a business acquisition for accounting purposes. ​ The Company has accounted for the acquisition of Uman as a purchase of a business under U.S. GAAP. Under the acquisition method of accounting, the assets and liabilities of Uman are recorded as of the acquisition date of July 1, 2019, at their respective fair values, and consolidated with those of the Company. Purchase consideration in excess of the amounts recognized for the net assets acquired was recognized as goodwill and is not expected to be tax deductible in any taxing jurisdiction. The following table summarizes the acquisition accounting, net of $1.2 million in cash and cash equivalents acquired (in thousands): ​ ​ ​ ​ ​ Purchase price: ​ ​ ​ Cash and stock paid ​ $ 21,217 Cash and cash equivalents acquired ​ ​ 1,221 Purchase price, net ​ ​ 19,996 ​ ​ ​ ​ Assets (liabilities) acquired: ​ ​ ​ Accounts receivable ​ $ 638 Inventory ​ ​ 1,680 Prepaids and other current assets ​ ​ 114 Property and equipment ​ ​ 33 Intangibles ​ ​ 13,450 Goodwill ​ ​ 8,111 Accounts payable ​ ​ (20) Accrued expense and other current liabilities ​ ​ (871) Deferred tax liabilities ​ ​ (3,139) Total ​ $ 19,996 ​ Revenue and net loss related to Uman’s operations were $1.5 million and $0.1 million, respectively for the year ended December 31, 2020 and is included in the Company’s consolidated statement of operations. Revenue and net income related to Uman’s operations were $1.1 million and less than $0.1 million, respectively, for the six months following the July 1, 2019 acquisition date, and is included in the Company’s consolidated statements of operations for the year ended December 31, 2019. The following unaudited pro forma information presents the condensed consolidated results of operations of the Company and Uman for the years ended December 31, 2020, 2019, and 2018 as if the acquisition of Uman had been completed on January 1, 2018. These pro forma condensed consolidated financial results have been prepared for comparative purposes only and include certain adjustments that reflect pro forma results of operations, such as increased amortization for the fair value of acquired intangible assets, increased cost of sales related to the inventory valuation adjustment, and adjustments relating to the tax effect of combining the Company and Uman businesses. The unaudited pro forma results do not reflect any operating efficiencies or potential cost savings which may result from the consolidation of the operations of the Company and Uman. Accordingly, these unaudited pro forma results are presented for informational purposes only and are not necessarily indicative of the results of operations that actually would have been achieved had the acquisition occurred as of January 1, 2018, nor are they intended to represent or be indicative of future results of operations (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ ​ Year Ended December 31, ​ ​ ​ ​ 2019 ​ ​ 2018 Revenue (unaudited) ​ ​ $ 57,597 ​ $ 38,753 Pre-tax loss (unaudited) ​ ​ $ (38,636) ​ $ (33,894) ​ During the year ended December 31, 2020, the Company incurred no costs associated with the acquisition of Uman. During the year ended December 31, 2019, the Company incurred $1.9 million in costs associated with the acquisition of Uman. Costs associated with the acquisition of Uman are recorded as selling, general, and administrative expenses within the consolidated statements of operations.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	12 Months Ended
	Dec. 31, 2020
Goodwill and Intangible Assets
Goodwill and Intangible Assets	16. Goodwill and intangible assets As of December 31, 2020 the carrying amount of goodwill was $10.5 million. The following is a rollforward of the Company’s goodwill balance (in thousands): ​ ​ ​ ​ ​ ​ ​ Goodwill Balance as of December 31, 2019 ​ $ 9,353 Cumulative translation adjustment ​ ​ 1,107 Balance as of December 31, 2020 ​ $ 10,460 ​ Acquired intangible assets consist of the following (dollars in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ ​ ​ ​ Gross ​ ​ ​ ​ Cumulative ​ Net ​ Weighted ​ ​ Estimated Useful ​ Carrying ​ Accumulated ​ Translation ​ Carrying ​ Average ​ Life (in years) Value Amortization Adjustment Value Life R emaining (in years) Know-how ​ 8.5 ​ $ 13,000 ​ $ (2,296) ​ $ 1,374 ​ $ 12,078 ​ 6.99 Developed technology 7 ​ ​ 1,650 ​ ​ (1,036) ​ ​ — ​ ​ 614 ​ 4.09 Customer relationships 8.5 - 10 ​ 1,360 ​ (618) ​ ​ 12 ​ 754 ​ 7.08 Non-compete agreements ​ 5.5 ​ ​ 340 ​ ​ (102) ​ ​ 31 ​ ​ 269 ​ 3.99 Trade names 3 ​ 50 ​ (49) ​ ​ — ​ 1 ​ 0.08 Total ​ ​ $ 16,400 ​ $ (4,101) ​ $ 1,417 ​ $ 13,716 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ ​ ​ Gross ​ ​ ​ ​ Cumulative ​ Net ​ Weighted ​ ​ Estimated Useful ​ Carrying ​ Accumulated ​ Translation ​ Carrying ​ Average ​ Life (in years) Value Amortization Adjustment Value Life R emaining (in years) Know-how ​ 8.5 ​ $ 13,000 ​ $ (767) ​ $ (99) ​ $ 12,134 ​ 8.00 Developed technology 7 ​ ​ 1,650 ​ ​ (737) ​ ​ — ​ ​ 913 ​ 5.09 Customer relationships 8.5 - 10 ​ 1,360 ​ (421) ​ ​ (1) ​ 938 ​ 8.08 Non-compete agreements ​ 5.5 ​ ​ 340 ​ ​ (34) ​ ​ (2) ​ ​ 304 ​ 5.00 Trade names 3 ​ 50 ​ (32) ​ ​ — ​ 18 ​ 1.09 Total ​ ​ $ 16,400 ​ $ (1,991) ​ $ (102) ​ $ 14,307 ​ ​ ​ The Company acquired $13.5 million of intangible assets in the Uman acquisition, of which $13.0 million was assigned to know-how, $0.4 million was assigned to non-compete agreements, and $0.1 million was assigned to customer relationships. The know-how and customer relationships intangible assets are being amortized on a straight-line basis over an 8.5 year amortization period, and the non-compete agreement intangible asset is being amortized on a straight-line basis over a 5.5 year amortization period. In total, the weighted-average amortization period for these intangible assets is 8.4 years. Know-how consists of the processes and procedures to produce Uman’s products. Customer relationships represent the underlying relationships with certain customers to provide continued product sale opportunities. The Company utilized excess earnings methodology to derive the fair value of the customer relationships. The Company recorded amortization expense of $2.1 million, $1.4 million, and $0.6 million for the years ended December 31, 2020, 2019, and 2018, respectively. Amortization of developed technology is recorded within research and development expenses, amortization of customer relationships is recorded within selling, general, and administrative expenses, amortization of trade names is recorded within selling, general, and administrative expenses, amortization of non-compete agreements is recorded within selling, general, and administrative expenses, and amortization of know-how is recorded within cost of goods sold. Future estimated amortization expense of acquired intangible assets as of December 31, 2020 is as follows (amounts in thousands): ​ ​ ​ ​ ​ For the Years Ended December 31, ​ Estimated Amortization Expense 2021 ​ $ 2,013 2022 ​ 1,930 2023 ​ 1,848 2024 ​ 1,733 Thereafter ​ 6,192 ​ ​ $ 13,716 ​

Related party transactions

Related party transactions	12 Months Ended
	Dec. 31, 2020
Related party transactions
Related party transactions	17. Related party transactions As described in Note 9, in June 2007, the Company entered into a 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 years ended December 31, 2020, 2019, and 2018 the Company recorded royalty expense of $1.1 million, $1.0 million, and $0.7 million, respectively, in cost of product revenue on the consolidated statements of operations. During the year ended December 31, 2020, the Company also incurred $1.0 million in cost of collaboration and license revenue owed to Tufts related to sublicensing certain technology and intellectual property to Abbott. During the year ended December 31, 2017, Harvard University became a related party because a member of the Company’s Board of Directors is affiliated with Harvard University. Revenue recorded from sales to Harvard University was $0.1 million, $0.1 million, and less than $0.1 million for the years ended December 31, 2020, 2019, and 2018, respectively. On November 28, 2018, the Company entered into a sponsor agreement with Powering Precision Health (PPH), a 501(c)6 not-for-profit entity of which an executive of the Company is a board member, through December 31, 2018. The agreement committed a maximum of $120,000 in funds and services to be provided to PPH for the term of the agreement. On November 14, 2019, the Company entered into the first amendment to the PPH sponsorship agreement. The agreement amended the $120,000 annual committed maximum amount to $200,000 for the annual committed amount. The agreement is terminable by either party and does not bind the Company to beyond the term of the agreement. For the year ended December 31, 2020, the company did not make any contributions. For the years ended December 31, 2019, and 2018, the Company had total contributions $0.1 million, and less than $0.1 million, respectively.

Restricted Cash

Restricted Cash	12 Months Ended
	Dec. 31, 2020
Restricted Cash
Restricted Cash	18. Restricted cash The Company’s restricted cash consists of cash that the Company is contractually obligated to maintain in accordance the terms of the Letter of Credit in the lease agreement. The $1.0 million Letter of Credit drawable by the lessor under specifically outlined conditions within the lease, which are primarily related to rent payments. 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 Company had $1.0 million of restricted cash as of December 31, 2020 and 2019, respectively.

Quarterly Data (Unaudited)

Quarterly Data (Unaudited)	12 Months Ended
	Dec. 31, 2020
Quarterly Data (Unaudited)
Quarterly Data (Unaudited)	19. Quarterly data (unaudited) (Amounts in thousands, except share and per share data) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 Q1 Q2 Q3 Q4 Total Year Product revenue ​ $ 9,833 ​ $ 6,790 ​ $ 11,662 ​ $ 15,732 ​ $ 44,017 Service and other revenue ​ 5,762 ​ 6,317 ​ 6,552 ​ 5,498 ​ 24,129 Collaboration and license revenue ​ 132 ​ 23 ​ 11,246 ​ 408 ​ 11,809 Grant revenue ​ ​ — ​ ​ — ​ ​ 1,929 ​ ​ 4,493 ​ ​ 6,422 Total revenue ​ 15,727 ​ 13,130 ​ 31,389 ​ 26,131 ​ 86,377 Costs of goods sold: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cost of product revenue ​ 6,186 ​ 5,416 ​ 6,387 ​ 7,961 ​ 25,950 Cost of services and other revenue ​ 2,728 ​ 2,501 ​ 2,896 ​ 3,120 ​ 11,245 Cost of collaboration and license revenue ​ ​ — ​ ​ — ​ ​ 1,000 ​ ​ — ​ ​ 1,000 Total costs of goods sold and services ​ 8,914 ​ 7,917 ​ 10,283 ​ 11,081 ​ 38,195 Gross profit ​ ​ 6,813 ​ ​ 5,213 ​ ​ 21,106 ​ ​ 15,050 ​ ​ 48,182 Operating expenses: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Research and development ​ 4,268 ​ 4,312 ​ 5,377 ​ 6,217 ​ 20,174 Selling, general and administrative ​ 14,273 ​ 13,102 ​ 13,451 ​ 18,766 ​ 59,592 Total operating expenses ​ 18,541 ​ 17,414 ​ 18,828 ​ 24,983 ​ 79,766 Income (loss) from operations ​ (11,728) ​ (12,201) ​ 2,278 ​ (9,933) ​ (31,584) Interest income (expense), net ​ 161 ​ (108) ​ (160) ​ (166) ​ (273) Other income (expense), net ​ (167) ​ (11) ​ (26) ​ 155 ​ (49) Income (loss) before income taxes ​ ​ (11,734) ​ ​ (12,320) ​ ​ 2,092 ​ ​ (9,944) ​ ​ (31,906) Income tax benefit ​ ​ 124 ​ ​ 18 ​ ​ 111 ​ ​ 123 ​ ​ 376 Net income (loss) ​ $ (11,610) ​ $ (12,302) ​ $ 2,203 ​ $ (9,821) ​ $ (31,530) Net income (loss) per share, basic ​ $ (0.41) ​ $ (0.43) ​ $ 0.07 ​ $ (0.31) ​ $ (1.07) Weighted-average common shares outstanding, basic ​ 28,179,132 ​ 28,312,925 ​ 30,139,157 ​ 31,696,002 ​ 29,589,132 Net income (loss) per share, diluted ​ $ (0.41) ​ $ (0.43) ​ $ 0.07 ​ $ (0.31) ​ $ (1.07) Weighted-average common shares outstanding, diluted ​ ​ 28,179,132 ​ ​ 28,312,925 ​ ​ 31,386,439 ​ ​ 31,696,002 ​ ​ 29,589,132 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019 Q1 Q2 Q3 Q4 Total Year Product revenue ​ $ 9,547 ​ $ 8,776 ​ $ 10,737 ​ $ 11,431 ​ $ 40,491 Service and other revenue ​ 2,790 ​ 4,760 ​ 4,207 ​ 4,302 ​ 16,059 Collaboration and license revenue ​ — ​ — ​ — ​ 184 ​ 184 Total revenue ​ 12,337 ​ 13,536 ​ 14,944 ​ 15,917 ​ 56,734 Costs of goods sold: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cost of product revenue ​ 4,248 ​ 4,455 ​ 5,513 ​ 6,684 ​ 20,900 Cost of services and other revenue ​ 2,082 ​ 2,150 ​ 2,398 ​ 2,368 ​ 8,998 Total costs of goods sold and services ​ 6,330 ​ 6,605 ​ 7,911 ​ 9,052 ​ 29,898 Gross profit ​ ​ 6,007 ​ ​ 6,931 ​ ​ 7,033 ​ ​ 6,865 ​ ​ 26,836 Operating expenses: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Research and development ​ 3,852 ​ 4,016 ​ 3,924 ​ 4,398 ​ 16,190 Selling, general and administrative ​ 11,512 ​ 13,429 ​ 13,352 ​ 13,953 ​ 52,246 Total operating expenses ​ 15,364 ​ 17,445 ​ 17,276 ​ 18,351 ​ 68,436 Loss from operations ​ (9,357) ​ (10,514) ​ (10,243) ​ (11,486) ​ (41,600) Interest income, net ​ 21 ​ 42 ​ 282 ​ 282 ​ 627 Other income (expense), net ​ (47) ​ (68) ​ (34) ​ 139 ​ (10) Loss before income taxes ​ ​ (9,383) ​ ​ (10,540) ​ ​ (9,995) ​ ​ (11,065) ​ ​ (40,983) Income tax benefit (provision) ​ ​ (22) ​ ​ (23) ​ ​ 125 ​ ​ 107 ​ ​ 187 Net loss ​ $ (9,405) ​ $ (10,563) ​ $ (9,870) ​ $ (10,958) ​ $ (40,796) Net loss per share, basic and diluted ​ $ (0.42) ​ $ (0.46) ​ $ (0.37) ​ $ (0.39) ​ $ (1.63) Weighted-average common shares outstanding, basic and diluted ​ 22,422,960 ​ 23,213,653 ​ 26,627,831 ​ 28,021,957 ​ 25,090,708 ​

Subsequent events

Subsequent events	12 Months Ended
	Dec. 31, 2020
Subsequent events
Subsequent events	20. Subsequent events ​ On February 3, 2021, the Company entered into an underwriting agreement with Goldman Sachs & Co. LLC, Leerink and Cowen, as representatives of the several underwriters, relating to an underwritten public offering of approximately 4,107,142 shares of the Company’s common stock, par value $0.001 per share. The underwritten public offering resulted in gross proceeds of $287.5 million. The Company incurred $17.9 million in issuance costs associated with the underwritten public offering, resulting in net proceeds to the Company of $269.6 million. ​

Significant accounting polici_2

Significant accounting policies (Policies)	12 Months Ended
	Dec. 31, 2020
Significant accounting policies
Principles of consolidation	Principles of consolidation The 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	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 assets acquired and liabilities assumed in acquisitions, valuation allowances recorded against deferred tax assets, and valuation of inventory. Actual results could differ from those estimates.
Income taxes	​
Revenue recognition	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 Accounting Standards Codification (ASC) Topic 606 Revenue from Contracts with Customers 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 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 recognized revenues from sales- or usage based royalties related to the Company’s licensing technology and intellectual property. 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 recorded sales- or usage-based royalty revenue for the years ended December 31, 2020 and 2019 related to the intellectual property licensed by Uman. The Company recognizes revenues from sales- or usage based royalty revenue at the later of when the sales or usage occurs; and the satisfaction or partial satisfaction of the performance obligation to which the royalty has been allocated. ​ 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. Occasionally the Company provides extended payment terms or financing arrangements to 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: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ December 31, 2020 (in thousands) NA EMEA Asia Pacific Total Product revenues ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Instruments $ 8,680 ​ $ 4,332 ​ $ 3,594 ​ $ 16,606 Consumable and other products ​ 14,305 ​ ​ 10,854 ​ ​ 2,252 ​ ​ 27,411 Totals $ 22,985 $ 15,186 $ 5,846 $ 44,017 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Service and other revenues ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Service-type warranties $ 3,171 ​ $ 1,543 ​ $ 207 ​ $ 4,921 Research services ​ 15,011 ​ ​ 2,225 ​ ​ 737 ​ 17,973 Other services ​ 700 ​ ​ 435 ​ ​ 100 ​ ​ 1,235 Totals ​ $ 18,882 ​ $ 4,203 ​ $ 1,044 ​ $ 24,129 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Collaboration and license revenue ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Collaboration and license revenue ​ $ 11,685 ​ $ 124 ​ $ — ​ $ 11,809 Totals $ 11,685 $ 124 $ — $ 11,809 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ December 31, 2019 (in thousands) NA EMEA Asia Pacific Total Product revenues ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Instruments $ 6,250 $ 5,243 $ 3,393 $ 14,886 Consumable and other products ​ 14,148 ​ 9,674 ​ 1,783 ​ 25,605 Totals $ 20,398 $ 14,917 $ 5,176 $ 40,491 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Service and other revenues ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Service-type warranties $ 3,139 $ 1,323 $ 171 $ 4,633 Research services ​ 8,845 ​ 704 ​ 456 ​ 10,005 Other services ​ 825 ​ 565 ​ 31 ​ 1,421 Totals ​ $ 12,809 ​ $ 2,592 ​ $ 658 ​ $ 16,059 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Collaboration and license revenue ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Collaboration and license revenue ​ $ 167 ​ $ 17 ​ $ — ​ $ 184 Totals $ 167 $ 17 $ — $ 184 ​ The Company’s contracts with customers may include promises to transfer multiple products and services to a customer. The Company combines 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. The aggregate amount of transaction price that is allocated to performance obligations that have not yet been satisfied or are partially satisfied as of December 31, 2020 is $6.0 million. Of the performance obligations not yet satisfied or are partially satisfied, $5.4 million is expected to be recognized as revenue in the next 12 months, with the remainder amounts Changes in deferred revenue from contracts with customers were as follows (in thousands): ​ ​ ​ ​ ​ Year Ended December 31, 2020 Balance at December 31, 2019 $ 5,163 Deferral of revenue ​ 6,955 Recognition of deferred revenue ​ (6,120) Balance at December 31, 2020 $ 5,998 ​ 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 changes in the balance of costs to obtain a contract are as follows (in thousands): ​ ​ ​ ​ ​ ​ Year Ended December 31, 2020 Balance at December 31, 2019 $ 335 Deferral of costs to obtain a contract ​ 506 Recognition of costs to obtain a contract ​ (593) Balance at December 31, 2020 $ 248 ​ 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 December 31, 2020 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 for the years ended December 31, 2020 and 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. ​ Grant revenue ​ The Company recognizes grant revenue as it performs services under the arrangement when the funding is committed. Revenues and related research and development expenses are presented gross in the consolidated statements of operations as the Company has determined it is the primary obligor under the arrangement relative to the research and development services. ​ Accounting for grants does not fall under ASC 606, as the grantor will not benefit directly from the Company’s expansion or product development. As there is no authoritative guidance under U.S. GAAP on accounting for government assistance to for-profit business entities, the Company has accounted for grants by analogy to International Accounting Standards (IAS) 20, Accounting for Government Grants and Disclosure of Government Assistance ​ Grants to the Company contain both monetary amounts granted related to assets and monetary amounts granted related to income, which are grants other than those related to assets. The grants related to assets are for the expansion and increase of manufacturing capacity. The grants related to income are for additional research and development, as well as other non-asset related scale up costs. ​ Under IAS 20, grants related to assets shall be presented in the consolidated balance sheets either by recognizing the grant as deferred income (which is recognized in the consolidated statements of operations on a systematic basis over the useful life of the asset), or by deducting the grant in calculating the carrying amount of the asset (which is recognized in the consolidated statements of operations over the life of the depreciable asset as a reduced depreciation expense). Both methods are acceptable under IAS 20. The Company has elected to record grants related to assets as a deduction in calculating the carrying value of the asset. ​ Under IAS 20, grants related to income are presented as part of the consolidated statements of operations, either separately or under a general heading. Both methods are acceptable under IAS 20. The Company has elected to record grants related to income separately on the consolidated statements of operations as grant revenue. The related expenses are recorded within operating expenses and not deducted. ​ On June 22, 2020, the Company entered into a workplan 1 award (WP1) with the National Institute of Health (NIH), under the Rapid Acceleration of Diagnostics (RADx) program to assess the feasibility of a novel SARS-CoV-2 antigen detection test using the Company’s Simoa technology. During the year ended December 31, 2020, the Company recognized $2.0 million of grant revenue and incurred $1.0 million in research and development expense related to WP1. WP1 is complete as of December 31, 2020. ​ On September 29, 2020, the Company entered into a workplan 2 award (WP2) with the NIH under its RADx program. WP2, which has a total award value of $18.2 million, accelerates the continued development, scale-up, and deployment of the novel SARS-CoV-2 antigen detection test using the Company’s Simoa technology. The contract provides funding to expand assay kit manufacturing capacity and commercial deployment readiness. Release of the $18.2 million of funding under WP2 is based on the achievement of certain milestones, and there is no assurance that the Company can meet all the milestones on a timely basis, if at all. If the Company does not meet all of the milestones, it will not be able access the full $18.2 million in funding under the contract. During the year ended December 31, 2020 the Company recognized $4.4 million in grant revenue and incurred $2.6 million in research and development expense related to WP2. ​ ​ ​ ​ ​ Total grant revenue from research and development activities $ 4,362 Total proceeds used for assets ​ 826 Total deferred proceeds for assets ​ 2,478 Total deferred grant revenue ​ 304 Total recognized $ 7,970 ​ ​ ​ Total recognized $ 7,970 Total amount accrued ​ (2,968) Total cash received $ 5,002 ​ ​ ​ Total proceeds received $ 5,002 Total proceeds reasonably assured ​ 13,198 Total WP2 grant amount $ 18,200
Business combinations	Business combinations Under the acquisition method of accounting, the Company generally recognizes the tangible and identifiable intangible assets acquired and liabilities assumed based on their estimated fair values on the date of acquisition. The fair values recognized, 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 value of acquired tangible and intangible assets, net of liabilities recognized, 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. 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.
Cost of revenue	Cost of revenue Cost of product revenue consists of raw materials, parts costs and associated freight, shipping and handling costs, contract manufacturer costs, personnel costs, yield loss, in-license payments and royalties, stock-based compensation, other direct costs and overhead. Cost of service and other revenue consists of personnel, facility costs associated with operating the Accelerator Labs on behalf of the customers, costs related to instrument maintenance and servicing equipment at customer sites, other direct and overhead. Cost of license revenue consists of license fees that are the direct results of cash payments received related to license agreements.
Research and development expenses	Research and development expenses Research and development expenses, including personnel costs, allocated facility costs, lab supplies, outside services, contract laboratory costs are charged to research and development expense as incurred. The Company accounts for nonrefundable advance payments for goods and services that will be used in future research and development activities as expense when the service has been performed or when the goods have been received. Expenses incurred related to grant funded activities are recorded in research and development expense.
Selling, general, and administrative expense	Selling, general, and administrative expenses Selling, general, and administrative expenses are primarily composed of compensation and benefits associated with sales and marketing, finance, human resources, and other administrative personnel, outside marketing, advertising, allocated facilities costs, legal expenses, and other general and administrative costs.
Net loss per share	Net loss per share Basic net loss per common share attributable to common stockholders is calculated by dividing the loss attributable to common stockholders by the weighted-average number of common shares. For purposes of the diluted net loss per share calculations, unvested restricted common stock, common stock options, and warrants are considered to be potentially dilutive securities, but are excluded from the 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): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ ​ 2020 2019 2018 Unvested restricted common stock and restricted stock units ​ 518,387 409,929 361,468 Outstanding stock options 2,494,045 2,507,062 2,476,911 Outstanding common stock warrants 10,000 10,000 76,041 Total 3,022,432 2,926,991 2,914,420 ​ As of December 31, 2020, 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.
Cash and Cash equivalents	Cash and cash equivalents Cash and cash equivalents consist of cash deposits and short-term, highly liquid investments that are readily convertible into cash, with original maturities of three months or less. Cash equivalents are carried at fair value based on quoted prices for identical assets. Cash and cash equivalents consist of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ ​ December 31, ​ 2020 2019 Cash ​ $ 19,535 ​ $ 6,406 Money market funds invested in U.S. Treasury obligations ​ 162,049 ​ 102,749 Total cash and cash equivalents ​ $ 181,584 ​ $ 109,155
Restricted cash and deposits	Restricted cash and deposits Restricted cash 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 December 31, 2020. As of both December 31, 2020 and 2019, the Company had $1.1 million in restricted cash and deposits related to amounts held for a line of credit, amounts held as a security deposit for the Company’s facility lease obligation, and a business registration application. As of both December 31, 2020 and 2019, $1.0 million of the $1.1 million was recorded on a separate line item as restricted cash. The remaining $0.1 million was included in noncurrent assets as of both December 31, 2020 and 2019.
Accounts Receivable and allowance for doubtful accounts	Accounts receivable and allowance for doubtful accounts The Company provides credit, in the normal course of business, to customers and does not require collateral. Accounts receivable consist of amounts due to the Company for sales to customers and are recorded net of an allowance for doubtful accounts. The Company reviews accounts receivable on a regular basis to determine if any receivable will potentially be uncollectable and to estimate the amount of allowance for doubtful accounts necessary. Once a receivable is deemed uncollectible, such balance is written off and charged against the allowance for doubtful accounts. The Company has not incurred material write offs in any of the periods presented. The Company’s allowance for doubtful accounts activity for the years ended December 31, 2020, 2019, and 2018 was as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2017 ​ $ — Additions ​ ​ 36 Deductions ​ ​ — December 31, 2018 ​ $ 36 Additions ​ ​ 160 Deductions ​ ​ (34) December 31, 2019 ​ $ 162 Additions ​ ​ 493 Deductions ​ ​ (285) December 31, 2020 ​ $ 370
Inventory	Inventory Inventory is stated at the lower of cost or market on a first-in, first-out (FIFO) basis. The Company analyzes its inventory levels on each reporting date and writes down inventory that is expected to expire prior to being sold and inventory in excess of expected sales requirements. In the event that the Company identifies these conditions exist in its inventory, the carrying value is reduced to its estimated net realizable value.
Property and equipment	Property and equipment Property and equipment, including leasehold improvements, are stated at cost and are depreciated, or amortized in the case of leasehold improvements, over their estimated useful lives using the straight-line method. Expenditures for maintenance and repairs are charged to expense as incurred, whereas major betterments are capitalized as additions to property and equipment. The Company reviews its property and equipment whenever events or changes in circumstances indicate that the carrying value of certain assets might not be recoverable and recognizes an impairment loss when it is probable that an asset’s realizable value is less than the carrying value. To date, no such impairment losses have been recorded. Depreciation is calculated based upon the following estimated useful lives of the assets: ​ ​ ​ ​ Laboratory and manufacturing equipment Five years Computers and software Three years Office furniture and equipment Seven years Leasehold improvements Shorter of the useful life of the asset or the remaining term of the lease ​
Software development costs	Software development costs The Company develops and modifies software related to the operation of the instrument. Software development costs are expensed as incurred until the point the Company establishes technological feasibility. Based on the Company’s product development process, technological feasibility is established upon the completion of a working model. The Company does not incur material costs between the completion of the working model and the point at which the product is ready for release. Therefore, software development costs are charged to the statement of operations as incurred as research and development expense.
Fair value of financial instruments	Fair value of financial instruments ​ ASC Topic 820, Fair Value Measurement ​ 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. ​ To the extent that the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair value requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized in Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement. ​ The carrying amount reflected on the balance sheets for cash and cash equivalents, accounts receivable, prepaid expenses and other current assets, accounts payable and accrued liabilities approximated their fair values, due to the short-term nature of these instruments. The carrying value of the long-term debt approximates its fair value as the debt arrangement is based on interest rates the Company believes it could obtain for borrowings with similar terms. The Company has an investment in the preferred stock of a privately held company which is recorded within other non-current assets on a cost basis. This cost method investment’s fair value has not been estimated as there are no identified events or changes in circumstances that would indicate a significant adverse effect on the fair value of the investment and to do so would be impractical. ​ Fair value measurements as of December 31, 2020 are as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Quoted prices ​ ​ ​ ​ Significant ​ ​ ​ ​ ​ in active ​ Significant other ​ unobservable ​ ​ ​ ​ ​ markets ​ observable ​ inputs Description Total (Level 1) inputs (Level 2) (Level 3) Financial assets ​ ​ ​ ​ ​ Cash equivalents $ 162,048 $ 162,048 ​ $ — $ — ​ ​ $ 162,048 ​ $ 162,048 ​ $ — ​ $ — ​ ​ Fair value measurements as of December 31, 2019 are as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Quoted prices ​ ​ ​ Significant ​ ​ ​ ​ ​ in active ​ Significant other ​ unobservable ​ ​ ​ ​ ​ markets ​ observable ​ inputs Description Total (Level 1) inputs (Level 2) (Level 3) Financial assets ​ ​ ​ ​ ​ Cash equivalents $ 102,749 $ 102,749 ​ $ — $ — ​ $ 102,749 $ 102,749 ​ $ — $ —
Warranties	Warranties ​ The Company provides a one-year warranty and maintenance service related to its instruments and sells extended warranty contracts for additional periods. The Company defers revenue associated with these services and recognizes them on a pro-rata basis over the period of service. ​
Credit, product and supplier concentrations and off-balance-sheet risk	Credit, product and supplier concentrations and off-balance-sheet risk The Company has no significant off-balance-sheet risk, such as foreign exchange contracts, option contracts, or other hedging arrangements. Financial instruments that potentially expose the Company to concentrations of credit risk primarily consist of cash and cash equivalents and a cost method investment. The Company places its cash and cash equivalents principally in depository accounts with a bank. The Company is also subject to supply chain risks related to the outsourcing of the manufacturing of its instruments. Although there are a limited number of manufacturers for instruments of this type, the Company believes that other suppliers could provide similar products on comparable terms. A change in suppliers, however, could cause a delay in manufacturing and a possible loss of sales, which would adversely affect operating results. In addition to outsourcing the manufacturing of its instruments, the Company also purchases antibodies through a number of different suppliers. Although a disruption in service from any one of its antibody suppliers is possible, the Company believes that it would be able to find an adequate supply from alternative suppliers. Customers outside the United States represented 29% and 50% of the Company’s gross trade accounts receivable balance as of December 31, 2020 and 2019, respectively. As of December 31, 2020, one customer represented 19% of the Company’s aggregate accounts receivable. As of December 31, 2019, and 2018, no single customer represented 10% of the Company’s aggregate accounts receivable. During the year ended December 31, 2020 one customer represented 13% of the Company’s total revenue. For the years ended December 31, 2019 and 2018, no single customer represented 10% of the Company’s total revenue.
Stock-based compensation	​ The Company accounts for stock-based compensation awards in accordance with ASC 718, Compensation—Stock Compensation Prior to the adoption of Accounting Standards Update (ASU) No. 2018-07, Compensation - Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting ​ Effective January 1, 2017, the Company ceased utilizing an estimated forfeiture rate and began recognizing forfeitures as they occur. The Company estimates the grant date fair value, and the resulting stock-based compensation expense, using the Black-Scholes option-pricing model. The grant date fair value of the stock-based awards is generally recognized on a straight-line basis over the requisite service period, which is generally the vesting period of the respective awards. The fair value of stock options granted to employees and non-employees is estimated on the grant date using the Black-Scholes option-pricing model, based on the assumptions noted in the following table: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ 2020 ​ 2019 ​ 2018 Risk-free interest rate 0.4% - 1.7% ​ 1.4% - 2.6% ​ 2.6% - 3.0% Expected dividend yield None ​ None ​ None Expected term (in years) 6 ​ 6.0 ​ 5.9 Expected volatility 43.9% - 49.2% ​ 33.5% - 39.7% ​ 32.4% - 36.8% ​ Using the Black-Scholes option-pricing model, the weighted-average grant date fair value of options granted for the years ended December 31, 2020, 2019, and 2018 was $12.66, $9.09, and $7.19 per share, respectively. Expected volatility was calculated based a proportional weighting of reported volatility data for a representative group of guideline publicly traded companies for which historical information was available, as well as the Company’s stock. The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the time of grant, commensurate with the expected life assumption. The Company estimates the expected life of options granted to employees utilizing the simplified method which calculates the expected life of an option as the average of the time to vesting and contractual life of the options. The expected life is applied to the stock option grant group as a whole, as the Company does not expect substantially different exercise or post-vesting termination behavior among its employee population. The Company uses the simplified method due to the lack of historical exercise data and the plain nature of the stock options. The Company uses the remaining contractual term for the expected life of non-employee awards. The expected dividend yield is assumed to be zero as the Company has never paid dividends and has no current plans to pay any dividends on common stock.
Recent accounting pronouncements	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. Recently Adopted On January 1, 2020, the Company adopted ASC Topic 842, Leases The Company elected the following practical expedients for all lease asset classes, which must be elected as a package and applied consistently to all of its leases at the transition date: i) the Company did not reassess whether any expired or existing contracts are or contain leases; ii) the Company did not reassess the lease classification for any expired or existing leases (that is, all existing leases that were classified as operating leases in accordance with ASC 840, Leases At the inception of an arrangement, the Company determines whether the arrangement is or contains a lease based on the facts and circumstances present in the arrangement. Leases with a term greater than one year are recognized on the balance sheet as right-of-use (ROU) assets and short-term and long-term lease liabilities, as applicable. The Company has elected the practical expedient not to recognize leases on the balance sheet with a term of twelve months or less. The Company’s leases consist of office and lab space and office equipment. All of the Company’s leases are classified as operating, and options to renew a lease are only included in the lease term to the extent those options are reasonably certain to be exercised. Additionally, the Company elected to apply the practical expedient not to separate lease and nonlease components for all leases. Operating lease liabilities and their corresponding ROU assets are initially recorded based on the present value of lease payments over the expected remaining lease term. The rate implicit in lease contracts is typically not readily determinable and, as a result, the Company utilizes its incremental borrowing rate to discount lease payments, which reflects the fixed rate at which the Company could borrow on a collateralized basis the amount of the lease payments, for a similar term, in a similar economic environment. To estimate its incremental borrowing rate, a credit rating applicable to the Company is estimated using a synthetic credit rating analysis since the Company does not currently have a rating agency-based credit rating. The adoption of ASC 842 resulted in the recognition of operating lease ROU assets and operating lease liabilities of $12.2 million and $22.8 million, respectively, on the Company’s condensed consolidated balance sheet, with the difference between the ROU asset and lease liability primarily attributable to unamortized lease incentives and deferred rent related to its lease for its corporate headquarters at 900 Middlesex Turnpike in Billerica, Massachusetts (the 900 Middlesex Turnpike Lease). On January 1, 2020, the Company adopted ASU 2017-04, “Intangibles – Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment” On January 1, 2020 the Company adopted ASU 2018-07. This standard simplifies the accounting for share-based payments to non-employees by aligning it with the accounting for share-based payments to employees, with certain exceptions. The adoption of ASU 2018-07 did not have a material effect on the Company’s consolidated financial statements. ​ On January 1, 2020, the Company adopted ASU No. 2018-13, “Fair Value Measurement (Topic 820), Disclosure Framework—Changes to the Disclosure Requirements for Fair Value Measurement” ​ ​ 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 an adjustment 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 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ adoption of ​ ​ As ​ ​ ​ Adjusted under ​ As reported ​ ​ ​ ASC 606 ​ reported ​ ​ ​ ASC 606 ​ December 31, ​ ​ December 31, ​ December 31, 2018 Adjustments January 1, 2019 2019 Adjustments 2019 Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Accounts receivable $ 6,792 $ 47 $ 6,839 $ 10,906 $ — $ 10,906 Prepaid expenses and other current assets ​ 2,330 ​ 288 ​ 2,618 ​ 2,137 ​ 335 ​ 1,802 Other non-current assets ​ 536 ​ 19 ​ 555 ​ 557 ​ — ​ 557 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Deferred revenue ​ 5,437 ​ 43 ​ 5,394 ​ 4,697 ​ (209) ​ 4,488 Deferred revenue, net of current portion ​ 520 ​ 43 ​ 477 ​ 466 ​ 14 ​ 480 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Stockholders’ equity: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Accumulated deficit $ (175,888) $ (440) $ (175,448) $ (216,244) $ (140) $ (216,104) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year Ended December 31, 2019 ​ ​ ​ ​ ​ ​ Under ASC ​ Under ASC 606 Adjustment 605 Product revenue $ 40,491 $ 55 $ 40,546 Service revenue ​ 16,059 ​ 273 ​ 16,332 Costs of goods sold and services ​ 29,898 ​ 1 ​ 29,899 Gross profit ​ 26,836 ​ 327 ​ 27,163 Selling general and administrative expenses ​ 52,246 ​ 27 ​ 52,273 Net loss $ (40,796) $ 300 $ (40,496) ​ In January of 2019, the Company adopted ASU 2016-01, 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 on the Company’s consolidated financial statements. ​ Not Yet Adopted 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 2022, with early adoption permitted. The Company does not expect impact of ASU 2016-13 to be material on its consolidated financial statements. ​ In August 2018, the FASB issued ASU No. 2018-15, Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract (ASU 2018-15) . This ASU addresses the accounting for implementation, setup and other upfront costs paid by a customer in a cloud computing or hosting arrangement. The guidance aligns the accounting treatment of these costs incurred in a hosting arrangement treated as a service contract with the requirements for capitalization and amortization costs to develop or obtain internal-use software. This guidance is effective for fiscal years beginning after December 15, 2020 and early adoption is permitted. The guidance can be adopted either retrospectively or prospectively. The Company is currently evaluating the expected impacts of ASU 2018-15. ​ In December 2019, the FASB issued ASU 2019-12, Income Taxes (ASC 740): Simplifying the Accounting for Income Taxes

Significant accounting polici_3

Significant accounting policies (Tables)	12 Months Ended
	Dec. 31, 2020
Revenue recognition
Schedule of disaggregated revenue	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ December 31, 2020 (in thousands) NA EMEA Asia Pacific Total Product revenues ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Instruments $ 8,680 ​ $ 4,332 ​ $ 3,594 ​ $ 16,606 Consumable and other products ​ 14,305 ​ ​ 10,854 ​ ​ 2,252 ​ ​ 27,411 Totals $ 22,985 $ 15,186 $ 5,846 $ 44,017 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Service and other revenues ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Service-type warranties $ 3,171 ​ $ 1,543 ​ $ 207 ​ $ 4,921 Research services ​ 15,011 ​ ​ 2,225 ​ ​ 737 ​ 17,973 Other services ​ 700 ​ ​ 435 ​ ​ 100 ​ ​ 1,235 Totals ​ $ 18,882 ​ $ 4,203 ​ $ 1,044 ​ $ 24,129 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Collaboration and license revenue ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Collaboration and license revenue ​ $ 11,685 ​ $ 124 ​ $ — ​ $ 11,809 Totals $ 11,685 $ 124 $ — $ 11,809 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ December 31, 2019 (in thousands) NA EMEA Asia Pacific Total Product revenues ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Instruments $ 6,250 $ 5,243 $ 3,393 $ 14,886 Consumable and other products ​ 14,148 ​ 9,674 ​ 1,783 ​ 25,605 Totals $ 20,398 $ 14,917 $ 5,176 $ 40,491 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Service and other revenues ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Service-type warranties $ 3,139 $ 1,323 $ 171 $ 4,633 Research services ​ 8,845 ​ 704 ​ 456 ​ 10,005 Other services ​ 825 ​ 565 ​ 31 ​ 1,421 Totals ​ $ 12,809 ​ $ 2,592 ​ $ 658 ​ $ 16,059 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Collaboration and license revenue ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Collaboration and license revenue ​ $ 167 ​ $ 17 ​ $ — ​ $ 184 Totals $ 167 $ 17 $ — $ 184
Schedule of changes in deferred revenue from contracts with customers	Changes in deferred revenue from contracts with customers were as follows (in thousands): ​ ​ ​ ​ ​ Year Ended December 31, 2020 Balance at December 31, 2019 $ 5,163 Deferral of revenue ​ 6,955 Recognition of deferred revenue ​ (6,120) Balance at December 31, 2020 $ 5,998
Schedule of costs to obtain a contract	The changes in the balance of costs to obtain a contract are as follows (in thousands): ​ ​ ​ ​ ​ ​ Year Ended December 31, 2020 Balance at December 31, 2019 $ 335 Deferral of costs to obtain a contract ​ 506 Recognition of costs to obtain a contract ​ (593) Balance at December 31, 2020 $ 248
Schedule of summary of the activity under WP2	​ ​ ​ ​ Total grant revenue from research and development activities $ 4,362 Total proceeds used for assets ​ 826 Total deferred proceeds for assets ​ 2,478 Total deferred grant revenue ​ 304 Total recognized $ 7,970 ​ ​ ​ Total recognized $ 7,970 Total amount accrued ​ (2,968) Total cash received $ 5,002 ​ ​ ​ Total proceeds received $ 5,002 Total proceeds reasonably assured ​ 13,198 Total WP2 grant amount $ 18,200
Schedule of outstanding potentially dilutive securities that have been excluded in the calculation of diluted net loss per share	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ ​ 2020 2019 2018 Unvested restricted common stock and restricted stock units ​ 518,387 409,929 361,468 Outstanding stock options 2,494,045 2,507,062 2,476,911 Outstanding common stock warrants 10,000 10,000 76,041 Total 3,022,432 2,926,991 2,914,420 ​
Schedule of cash and cash equivalents	Cash and cash equivalents consist of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ ​ December 31, ​ 2020 2019 Cash ​ $ 19,535 ​ $ 6,406 Money market funds invested in U.S. Treasury obligations ​ 162,049 ​ 102,749 Total cash and cash equivalents ​ $ 181,584 ​ $ 109,155
Schedule of allowance for doubtful accounts	The Company’s allowance for doubtful accounts activity for the years ended December 31, 2020, 2019, and 2018 was as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2017 ​ $ — Additions ​ ​ 36 Deductions ​ ​ — December 31, 2018 ​ $ 36 Additions ​ ​ 160 Deductions ​ ​ (34) December 31, 2019 ​ $ 162 Additions ​ ​ 493 Deductions ​ ​ (285) December 31, 2020 ​ $ 370
Schedule of estimated useful lives	​ ​ ​ ​ Laboratory and manufacturing equipment Five years Computers and software Three years Office furniture and equipment Seven years Leasehold improvements Shorter of the useful life of the asset or the remaining term of the lease
Schedule of fair value measurements	​ Fair value measurements as of December 31, 2020 are as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Quoted prices ​ ​ ​ ​ Significant ​ ​ ​ ​ ​ in active ​ Significant other ​ unobservable ​ ​ ​ ​ ​ markets ​ observable ​ inputs Description Total (Level 1) inputs (Level 2) (Level 3) Financial assets ​ ​ ​ ​ ​ Cash equivalents $ 162,048 $ 162,048 ​ $ — $ — ​ ​ $ 162,048 ​ $ 162,048 ​ $ — ​ $ — ​ ​ Fair value measurements as of December 31, 2019 are as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Quoted prices ​ ​ ​ Significant ​ ​ ​ ​ ​ in active ​ Significant other ​ unobservable ​ ​ ​ ​ ​ markets ​ observable ​ inputs Description Total (Level 1) inputs (Level 2) (Level 3) Financial assets ​ ​ ​ ​ ​ Cash equivalents $ 102,749 $ 102,749 ​ $ — $ — ​ $ 102,749 $ 102,749 ​ $ — $ —
Summary of fair value assumptions of stock options granted to employees and directors for their services on the Company's Board of Directors	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ 2020 ​ 2019 ​ 2018 Risk-free interest rate 0.4% - 1.7% ​ 1.4% - 2.6% ​ 2.6% - 3.0% Expected dividend yield None ​ None ​ None Expected term (in years) 6 ​ 6.0 ​ 5.9 Expected volatility 43.9% - 49.2% ​ 33.5% - 39.7% ​ 32.4% - 36.8%
ASU 2014-09
Revenue recognition
Schedule of impact on consolidated balance sheet and statement of operations due to adoption of ASU 606	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 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ adoption of ​ ​ As ​ ​ ​ Adjusted under ​ As reported ​ ​ ​ ASC 606 ​ reported ​ ​ ​ ASC 606 ​ December 31, ​ ​ December 31, ​ December 31, 2018 Adjustments January 1, 2019 2019 Adjustments 2019 Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Accounts receivable $ 6,792 $ 47 $ 6,839 $ 10,906 $ — $ 10,906 Prepaid expenses and other current assets ​ 2,330 ​ 288 ​ 2,618 ​ 2,137 ​ 335 ​ 1,802 Other non-current assets ​ 536 ​ 19 ​ 555 ​ 557 ​ — ​ 557 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Deferred revenue ​ 5,437 ​ 43 ​ 5,394 ​ 4,697 ​ (209) ​ 4,488 Deferred revenue, net of current portion ​ 520 ​ 43 ​ 477 ​ 466 ​ 14 ​ 480 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Stockholders’ equity: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Accumulated deficit $ (175,888) $ (440) $ (175,448) $ (216,244) $ (140) $ (216,104) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the year Ended December 31, 2019 ​ ​ ​ ​ ​ ​ Under ASC ​ Under ASC 606 Adjustment 605 Product revenue $ 40,491 $ 55 $ 40,546 Service revenue ​ 16,059 ​ 273 ​ 16,332 Costs of goods sold and services ​ 29,898 ​ 1 ​ 29,899 Gross profit ​ 26,836 ​ 327 ​ 27,163 Selling general and administrative expenses ​ 52,246 ​ 27 ​ 52,273 Net loss $ (40,796) $ 300 $ (40,496)

Inventory (Tables)

Inventory (Tables)	12 Months Ended
	Dec. 31, 2020
Inventory
Summary of inventory	Inventory consists of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2020 2019 Raw materials ​ $ 5,265 ​ $ 4,717 Work in process ​ 3,306 ​ 2,573 Finished goods ​ 6,285 ​ 3,173 Total ​ $ 14,856 ​ $ 10,463

Property and equipment (Tables)

Property and equipment (Tables)	12 Months Ended
	Dec. 31, 2020
Property and equipment
Schedule of Property and equipment	Property and equipment consists of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As of ​ ​ December 31, ​ 2020 2019 Laboratory and manufacturing equipment ​ $ 8,523 ​ $ 5,391 Office furniture and equipment ​ 1,556 ​ 1,403 Computers and software ​ 1,504 ​ 1,103 Leasehold improvements ​ 8,765 ​ 8,489 Total ​ $ 20,348 ​ $ 16,386 ​ ​ ​ ​ ​ Less: accumulated depreciation ​ (6,436) ​ (4,339) Total ​ $ 13,912 ​ $ 12,047

Other accrued expenses (Tables)

Other accrued expenses (Tables)	12 Months Ended
	Dec. 31, 2020
Other accrued expenses
Summary of other accrued expenses	Other accrued expenses consist of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ December 31, ​ 2020 2019 Accrued inventory purchases ​ $ 527 ​ $ 459 Accrued royalties ​ 1,845 ​ 476 Accrued professional services ​ 797 ​ 655 Accrued development costs ​ 323 ​ 151 Accrued other ​ 1,353 ​ 757 Total accrued expenses ​ $ 4,845 ​ $ 2,498
Summary of other non-current liabilities	Other non-current liabilities consist of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ December 31, ​ ​ 2020 ​ 2019 Leasehold obligation incentive ​ $ — ​ $ 7,572 Deferred rent ​ ​ — ​ ​ 3,009 Deferred tax liabilities ​ ​ 2,649 ​ ​ 2,825 Other ​ ​ — ​ ​ 1 Total other non-current liabilities ​ $ 2,649 ​ $ 13,407

Income taxes (Tables)

Income taxes (Tables)	12 Months Ended
	Dec. 31, 2020
Income taxes
Schedule of components of income (loss) before income taxes	The following table presents the components of loss before income taxes (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ ​ 2020 ​ 2019 2018 United States ​ $ (29,896) ​ $ (40,010) ​ $ (31,436) Foreign ​ (2,010) ​ (973) ​ (75) ​ ​ $ (31,906) ​ $ (40,983) ​ $ (31,511) ​
Schedule of provision for (benefit from) income taxes	The following table summarizes income tax benefit (provision) (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ December 31, ​ 2020 2019 2018 Current: ​ ​ ​ ​ ​ ​ ​ ​ ​ United States ​ ​ ​ ​ ​ ​ ​ ​ ​ Federal $ — $ — $ — State ​ ​ (13) ​ ​ (20) ​ ​ (18) Foreign ​ ​ (102) ​ ​ (93) ​ ​ — Total current income tax provision ​ ​ (115) ​ ​ (113) ​ ​ (18) Deferred ​ ​ ​ ​ ​ ​ ​ ​ ​ United States ​ ​ ​ ​ ​ ​ ​ ​ ​ Federal ​ ​ (8) ​ ​ (3) ​ ​ (2) State ​ ​ (3) ​ ​ (1) ​ ​ (5) Foreign ​ ​ 502 ​ ​ 304 ​ ​ — Total deferred income tax benefit (provision) ​ ​ 491 ​ ​ 300 ​ ​ (7) Total income tax benefit (provision) $ 376 ​ $ 187 ​ $ (25)
Schedule of reconciliation of the federal statutory income tax rate to the effective tax rate	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ ​ 2020 2019 2018 Federal statutory income tax rate 21.0 % 21.0 % 21.0 % Foreign tax rate differential 0.3 % — % — % State taxes, net of federal benefit 2.5 % 3.2 % 6.0 % Tax credits 1.6 % 2.3 % 2.7 % Share-based compensation 5.2 % 2.3 % 1.1 % Permanent items (0.4) % (0.9) % (1.2) % Deferred tax rate change ​ 0.3 % (1.4) % — % Change in valuation allowance (29.7) % (24.6) % (29.9) % Other ​ 0.4 % (1.4) % 0.2 % Effective income tax rate 1.2 % 0.5 % (0.1) %
Schedule of deferred tax assets and liabilities	​ Deferred tax assets and liabilities reflect the net tax effects of temporary differences between the carrying amount of assets and liabilities for financial reporting and the amounts used for income tax purposes. Significant components of the Company’s deferred tax assets and liabilities were as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2020 2019 Deferred tax assets: ​ ​ Net operating loss carryforwards ​ $ 50,233 ​ $ 43,814 Tax credits ​ 5,101 ​ 5,518 Deferred revenue ​ ​ 2,167 ​ ​ 1,247 Amortization ​ ​ 1,054 ​ ​ 928 Stock-based compensation ​ 1,956 ​ 973 Deferred rent ​ ​ — ​ ​ 727 Lease incentive obligation ​ ​ — ​ ​ 1,828 Lease liability ​ ​ 5,703 ​ ​ — Other deferred tax assets ​ ​ 2,533 ​ ​ 1,325 Total deferred tax assets ​ 68,747 ​ 56,360 Less: valuation allowances ​ ​ (63,609) ​ ​ (54,137) Net deferred tax assets ​ ​ 5,138 ​ ​ 2,223 Deferred tax liabilities: ​ ​ ​ ​ ​ ​ Right-of-Use Assets ​ ​ (2,957) ​ ​ — Depreciation ​ ​ (1,775) ​ ​ (1,769) Amortization acquired intangibles ​ ​ (2,880) ​ ​ (3,031) Inventory ​ ​ (64) ​ ​ (212) Goodwill ​ ​ (49) ​ ​ (31) Other deferred tax liabilities ​ ​ (61) ​ ​ (5) Net deferred tax liabilities ​ $ (2,648) ​ $ (2,825)
Summary of Valuation Allowance	​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 2019 Balance, beginning of year ​ $ 54,137 ​ $ 44,033 Change in valuation allowance ​ ​ 9,472 ​ ​ 10,104 Balance, end of year ​ $ 63,609 ​ $ 54,137

Common Stock, warrants, stock_2

Common Stock, warrants, stock-based compensation, stock options, restricted stock and restricted stock units (Tables)	12 Months Ended
	Dec. 31, 2020
Common Stock, warrants, stock-based compensation, stock options, restricted stock and restricted stock units
Schedule of common stock reserved	​ ​ ​ ​ ​ ​ ​ ​ As of December 31, ​ 2020 2019 Common stock warrants 10,000 10,000 Common stock options and unvested restricted common stock 3,012,432 2,916,991 Shares reserved for future awards under compensation plans 1,559,108 882,715 ​ 4,581,540 3,809,706
Summary of warrant activity	​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ Issued and ​ Average ​ exercisable Exercise Price As of December 31, 2019 10,000 ​ $ 21.00 Issued — ​ — Exercised — ​ — Cancelled — ​ ​ — As of December 31, 2020 10,000 ​ $ 21.00
Summary of share-based compensation expense for all stock awards	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ ​ ​ 2020 2019 2018 Cost of product revenue ​ ​ $ 189 ​ $ 86 ​ $ 55 Cost of service and other revenue ​ ​ 311 ​ 238 ​ 173 Research and development ​ ​ 1,129 ​ 718 ​ 513 Selling, general, and administrative ​ ​ 8,470 ​ 5,346 ​ 4,143 Total ​ ​ $ 10,099 ​ $ 6,388 ​ $ 4,884
Summary of stock option activity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted-average ​ Remaining contractual ​ Aggregate intrinsic value ​ Options exercise price life (in years) (in thousands) Outstanding at December 31, 2019 2,507,062 $ 14.41 ​ 7.58 ​ $ 24,870 Granted 550,290 ​ $ 28.39 ​ ​ ​ ​ ​ Exercised (407,687) ​ $ 9.85 ​ ​ ​ ​ ​ Cancelled (155,620) ​ $ 22.58 ​ ​ ​ ​ ​ Outstanding at December 31, 2020 2,494,045 ​ $ 17.73 ​ 7.27 ​ $ 71,760 Vested and expected to vest at December 31, 2020 2,494,045 ​ $ 17.73 ​ 7.27 ​ $ 71,760 Exercisable at December 31, 2020 ​ 1,514,576 ​ $ 12.54 ​ 6.42 ​ $ 51,430
Summary of restricted stock units activity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted-average ​ ​ ​ ​ grant date ​ ​ ​ ​ fair value ​ Shares per share Unvested RSUs as of December 31, 2019 370,123 $ 20.48 Granted 334,665 ​ $ 31.99 Vested (182,036) ​ $ 20.13 Cancelled (44,171) ​ $ 26.79 Unvested RSUs as of December 31, 2020 478,581 ​ $ 28.08

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2020
Leases
Summary of the lease costs recognized under ASC 842	The following table contains a summary of the lease costs recognized under ASC 842 and other information pertaining to the Company’s operating leases for the year ended December 31, 2020: ​ ​ ​ ​ ​ ​ Operating leases (in thousands) ​ ​ For the year ended December 31, 2020 Lease Costs (1) ​ ​ ​ ​ Operating lease costs ​ ​ $ 2,663 Total lease cost ​ ​ $ 2,663 ​ ​ ​ ​ ​ Other information ​ ​ ​ ​ Operating cash flows used for operating leases ​ ​ $ 2,108 Weighted average remaining lease term (years) ​ ​ ​ 9.8 Weighted average discount rate ​ ​ ​ 9.73% ​ (1) Short-term lease costs and variable lease costs incurred by the Company for the year ended December 31, 2020 were considered immaterial. ​
Schedule of future minimum commitments under ASC 842	​ ​ ​ ​ ​ Maturity of lease liabilities (in thousands) ​ As of December 31, 2020 2021 ​ $ 3,388 2022 ​ ​ 3,466 2023 ​ ​ 3,515 2024 ​ ​ 3,577 2025 and thereafter ​ ​ 22,203 Total lease payments ​ $ 36,149 Less: imputed interest ​ ​ 13,024 Total operating lease liabilities ​ $ 23,125

Notes payable (Tables)

Notes payable (Tables)	12 Months Ended
	Dec. 31, 2020
Notes payable
Schedule of debt payment obligations due based on principal payments	As of December 31, 2020, debt payment obligations due based on principal payments are as follows (in thousands): ​ ​ ​ ​ ​ 2021 ​ $ 7,688 Total ​ $ 7,688

Business combinations (Tables)

Business combinations (Tables)	12 Months Ended
	Dec. 31, 2020
Aushon acquisition
Schedule of fair value of consideration transferred	The following table presents acquisition accounting as of January 30, 2018 (in thousands): ​ ​ ​ ​ Fair value of consideration transferred: ​ Cash ​ $ 3,200 Obligation to issue cash ​ 800 Total acquisition consideration ​ $ 4,000 ​ ​ ​ ​ Fair value of assets acquired and liabilities assumed: ​ Cash and cash equivalents ​ $ 199 Accounts receivable ​ 210 Inventory ​ 828 Prepaid expenses ​ 71 Property and equipment and other non-current assets ​ 180 Intangible Assets ​ 2,950 Goodwill ​ 1,308 Total assets acquired ​ 5,746 Contractual obligations ​ (1,155) Accounts payable and accrued liabilities ​ (591) Net assets acquired ​ $ 4,000
UmanDiagnostics AB Acquisition
Schedule of fair value of consideration transferred	The following table summarizes the acquisition accounting, net of $1.2 million in cash and cash equivalents acquired (in thousands): ​ ​ ​ ​ ​ Purchase price: ​ ​ ​ Cash and stock paid ​ $ 21,217 Cash and cash equivalents acquired ​ ​ 1,221 Purchase price, net ​ ​ 19,996 ​ ​ ​ ​ Assets (liabilities) acquired: ​ ​ ​ Accounts receivable ​ $ 638 Inventory ​ ​ 1,680 Prepaids and other current assets ​ ​ 114 Property and equipment ​ ​ 33 Intangibles ​ ​ 13,450 Goodwill ​ ​ 8,111 Accounts payable ​ ​ (20) Accrued expense and other current liabilities ​ ​ (871) Deferred tax liabilities ​ ​ (3,139) Total ​ $ 19,996
Schedule of fair value of assets acquired and liabilities assumed	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ ​ Year Ended December 31, ​ ​ ​ ​ 2019 ​ ​ 2018 Revenue (unaudited) ​ ​ $ 57,597 ​ $ 38,753 Pre-tax loss (unaudited) ​ ​ $ (38,636) ​ $ (33,894)

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2020
Goodwill and 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, 2019 ​ $ 9,353 Cumulative translation adjustment ​ ​ 1,107 Balance as of December 31, 2020 ​ $ 10,460
Summary of intangible assets	Acquired intangible assets consist of the following (dollars in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ ​ ​ ​ ​ ​ Gross ​ ​ ​ ​ Cumulative ​ Net ​ Weighted ​ ​ Estimated Useful ​ Carrying ​ Accumulated ​ Translation ​ Carrying ​ Average ​ Life (in years) Value Amortization Adjustment Value Life R emaining (in years) Know-how ​ 8.5 ​ $ 13,000 ​ $ (2,296) ​ $ 1,374 ​ $ 12,078 ​ 6.99 Developed technology 7 ​ ​ 1,650 ​ ​ (1,036) ​ ​ — ​ ​ 614 ​ 4.09 Customer relationships 8.5 - 10 ​ 1,360 ​ (618) ​ ​ 12 ​ 754 ​ 7.08 Non-compete agreements ​ 5.5 ​ ​ 340 ​ ​ (102) ​ ​ 31 ​ ​ 269 ​ 3.99 Trade names 3 ​ 50 ​ (49) ​ ​ — ​ 1 ​ 0.08 Total ​ ​ $ 16,400 ​ $ (4,101) ​ $ 1,417 ​ $ 13,716 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ ​ ​ ​ Gross ​ ​ ​ ​ Cumulative ​ Net ​ Weighted ​ ​ Estimated Useful ​ Carrying ​ Accumulated ​ Translation ​ Carrying ​ Average ​ Life (in years) Value Amortization Adjustment Value Life R emaining (in years) Know-how ​ 8.5 ​ $ 13,000 ​ $ (767) ​ $ (99) ​ $ 12,134 ​ 8.00 Developed technology 7 ​ ​ 1,650 ​ ​ (737) ​ ​ — ​ ​ 913 ​ 5.09 Customer relationships 8.5 - 10 ​ 1,360 ​ (421) ​ ​ (1) ​ 938 ​ 8.08 Non-compete agreements ​ 5.5 ​ ​ 340 ​ ​ (34) ​ ​ (2) ​ ​ 304 ​ 5.00 Trade names 3 ​ 50 ​ (32) ​ ​ — ​ 18 ​ 1.09 Total ​ ​ $ 16,400 ​ $ (1,991) ​ $ (102) ​ $ 14,307 ​ ​
Schedule of future estimated amortization expense of acquired intangible assets	Future estimated amortization expense of acquired intangible assets as of December 31, 2020 is as follows (amounts in thousands): ​ ​ ​ ​ ​ For the Years Ended December 31, ​ Estimated Amortization Expense 2021 ​ $ 2,013 2022 ​ 1,930 2023 ​ 1,848 2024 ​ 1,733 Thereafter ​ 6,192 ​ ​ $ 13,716

Quarterly Data (Unaudited) (Tab

Quarterly Data (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2020
Quarterly Data (Unaudited)
Quarterly Data (Unaudited)	(Amounts in thousands, except share and per share data) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2020 Q1 Q2 Q3 Q4 Total Year Product revenue ​ $ 9,833 ​ $ 6,790 ​ $ 11,662 ​ $ 15,732 ​ $ 44,017 Service and other revenue ​ 5,762 ​ 6,317 ​ 6,552 ​ 5,498 ​ 24,129 Collaboration and license revenue ​ 132 ​ 23 ​ 11,246 ​ 408 ​ 11,809 Grant revenue ​ ​ — ​ ​ — ​ ​ 1,929 ​ ​ 4,493 ​ ​ 6,422 Total revenue ​ 15,727 ​ 13,130 ​ 31,389 ​ 26,131 ​ 86,377 Costs of goods sold: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cost of product revenue ​ 6,186 ​ 5,416 ​ 6,387 ​ 7,961 ​ 25,950 Cost of services and other revenue ​ 2,728 ​ 2,501 ​ 2,896 ​ 3,120 ​ 11,245 Cost of collaboration and license revenue ​ ​ — ​ ​ — ​ ​ 1,000 ​ ​ — ​ ​ 1,000 Total costs of goods sold and services ​ 8,914 ​ 7,917 ​ 10,283 ​ 11,081 ​ 38,195 Gross profit ​ ​ 6,813 ​ ​ 5,213 ​ ​ 21,106 ​ ​ 15,050 ​ ​ 48,182 Operating expenses: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Research and development ​ 4,268 ​ 4,312 ​ 5,377 ​ 6,217 ​ 20,174 Selling, general and administrative ​ 14,273 ​ 13,102 ​ 13,451 ​ 18,766 ​ 59,592 Total operating expenses ​ 18,541 ​ 17,414 ​ 18,828 ​ 24,983 ​ 79,766 Income (loss) from operations ​ (11,728) ​ (12,201) ​ 2,278 ​ (9,933) ​ (31,584) Interest income (expense), net ​ 161 ​ (108) ​ (160) ​ (166) ​ (273) Other income (expense), net ​ (167) ​ (11) ​ (26) ​ 155 ​ (49) Income (loss) before income taxes ​ ​ (11,734) ​ ​ (12,320) ​ ​ 2,092 ​ ​ (9,944) ​ ​ (31,906) Income tax benefit ​ ​ 124 ​ ​ 18 ​ ​ 111 ​ ​ 123 ​ ​ 376 Net income (loss) ​ $ (11,610) ​ $ (12,302) ​ $ 2,203 ​ $ (9,821) ​ $ (31,530) Net income (loss) per share, basic ​ $ (0.41) ​ $ (0.43) ​ $ 0.07 ​ $ (0.31) ​ $ (1.07) Weighted-average common shares outstanding, basic ​ 28,179,132 ​ 28,312,925 ​ 30,139,157 ​ 31,696,002 ​ 29,589,132 Net income (loss) per share, diluted ​ $ (0.41) ​ $ (0.43) ​ $ 0.07 ​ $ (0.31) ​ $ (1.07) Weighted-average common shares outstanding, diluted ​ ​ 28,179,132 ​ ​ 28,312,925 ​ ​ 31,386,439 ​ ​ 31,696,002 ​ ​ 29,589,132 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019 Q1 Q2 Q3 Q4 Total Year Product revenue ​ $ 9,547 ​ $ 8,776 ​ $ 10,737 ​ $ 11,431 ​ $ 40,491 Service and other revenue ​ 2,790 ​ 4,760 ​ 4,207 ​ 4,302 ​ 16,059 Collaboration and license revenue ​ — ​ — ​ — ​ 184 ​ 184 Total revenue ​ 12,337 ​ 13,536 ​ 14,944 ​ 15,917 ​ 56,734 Costs of goods sold: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Cost of product revenue ​ 4,248 ​ 4,455 ​ 5,513 ​ 6,684 ​ 20,900 Cost of services and other revenue ​ 2,082 ​ 2,150 ​ 2,398 ​ 2,368 ​ 8,998 Total costs of goods sold and services ​ 6,330 ​ 6,605 ​ 7,911 ​ 9,052 ​ 29,898 Gross profit ​ ​ 6,007 ​ ​ 6,931 ​ ​ 7,033 ​ ​ 6,865 ​ ​ 26,836 Operating expenses: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Research and development ​ 3,852 ​ 4,016 ​ 3,924 ​ 4,398 ​ 16,190 Selling, general and administrative ​ 11,512 ​ 13,429 ​ 13,352 ​ 13,953 ​ 52,246 Total operating expenses ​ 15,364 ​ 17,445 ​ 17,276 ​ 18,351 ​ 68,436 Loss from operations ​ (9,357) ​ (10,514) ​ (10,243) ​ (11,486) ​ (41,600) Interest income, net ​ 21 ​ 42 ​ 282 ​ 282 ​ 627 Other income (expense), net ​ (47) ​ (68) ​ (34) ​ 139 ​ (10) Loss before income taxes ​ ​ (9,383) ​ ​ (10,540) ​ ​ (9,995) ​ ​ (11,065) ​ ​ (40,983) Income tax benefit (provision) ​ ​ (22) ​ ​ (23) ​ ​ 125 ​ ​ 107 ​ ​ 187 Net loss ​ $ (9,405) ​ $ (10,563) ​ $ (9,870) ​ $ (10,958) ​ $ (40,796) Net loss per share, basic and diluted ​ $ (0.42) ​ $ (0.46) ​ $ (0.37) ​ $ (0.39) ​ $ (1.63) Weighted-average common shares outstanding, basic and diluted ​ 22,422,960 ​ 23,213,653 ​ 26,627,831 ​ 28,021,957 ​ 25,090,708

Organization and operations (De

Organization and operations (Details) - USD ($) $ / shares in Units, $ in Thousands	Aug. 06, 2020	Aug. 08, 2019	Jun. 05, 2019	Aug. 31, 2020	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Aug. 01, 2019	Jul. 01, 2019	Mar. 19, 2019	Jan. 01, 2019
Initial Public Offering
Stock Issued During Period, Shares, New Issues		2,700,000
Common stock, authorized shares					120,000,000				120,000,000				120,000,000	120,000,000	120,000,000
Common stock, par value					$ 0.001				$ 0.001				$ 0.001	$ 0.001	$ 0.001
Common stock, aggregate offering price					$ 32				$ 28				$ 28	$ 32	$ 28
Accumulated deficit					(247,774)				(216,244)				(216,244)	(247,774)	(216,244)	$ (175,888)				$ (175,448)
Net loss					(9,821)	$ 2,203	$ (12,302)	$ (11,610)	(10,958)	$ (9,870)	$ (10,563)	$ (9,405)		(31,530)	(40,796)	(31,536)
Unrestricted cash and cash equivalents					$ 181,584				$ 109,155				109,155	181,584	109,155	$ 44,429
Underwritten public offering
Initial Public Offering
Stock Issued During Period, Shares, New Issues	3,000,000	2,700,000		3,000,000
Common stock, par value	$ 0.001	$ 0.001		$ 0.001
Gross Proceeds From Issuance Of Common Stock	$ 97,600	$ 69,000		$ 97,600
Stock issuance cost	6,200	4,500		6,200
Sale of common stock in at-the-market offering, net	$ 91,400	$ 64,500		$ 91,400										91,404	64,529
At-the-market offering
Initial Public Offering
Stock Issued During Period, Shares, New Issues			2,200,000
Shares issued price (in dollars per share)			$ 22.73
Common stock, par value																			$ 0.001
Gross Proceeds From Issuance Of Common Stock			$ 49,700
Stock issuance cost			1,700
Sale of common stock in at-the-market offering, net			$ 48,000												$ 48,019
At-the-market offering | Maximum
Initial Public Offering
Common stock, aggregate offering price																			$ 50,000
UmanDiagnostics AB Acquisition
Initial Public Offering
Capital stock shares outstanding, percent																	95.00%	5.00%
Net loss														$ (100)
UmanDiagnostics AB Acquisition | Maximum
Initial Public Offering
Net loss													$ 100

Significant accounting polici_4

Significant accounting policies - Customers (Details)	12 Months Ended
	Dec. 31, 2020
Minimum
Revenue recognition
Period of payment	30 days
Maximum
Revenue recognition
Period of payment	45 days

Significant accounting polici_5

Significant accounting policies - Disaggregated revenue (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenue recognition
Total revenue	$ 26,131	$ 31,389	$ 13,130	$ 15,727	$ 15,917	$ 14,944	$ 13,536	$ 12,337	$ 86,377	$ 56,734	$ 37,632
Product revenue
Revenue recognition
Total revenue	15,732	11,662	6,790	9,833	11,431	10,737	8,776	9,547	44,017	40,491	23,365
Product revenue | NA
Revenue recognition
Total revenue									22,985	20,398
Product revenue | EMEA
Revenue recognition
Total revenue									15,186	14,917
Product revenue | Asia Pacific
Revenue recognition
Total revenue									5,846	5,176
Instruments
Revenue recognition
Total revenue									16,606	14,886
Instruments | NA
Revenue recognition
Total revenue									8,680	6,250
Instruments | EMEA
Revenue recognition
Total revenue									4,332	5,243
Instruments | Asia Pacific
Revenue recognition
Total revenue									3,594	3,393
Consumable and other products
Revenue recognition
Total revenue									27,411	25,605
Consumable and other products | NA
Revenue recognition
Total revenue									14,305	14,148
Consumable and other products | EMEA
Revenue recognition
Total revenue									10,854	9,674
Consumable and other products | Asia Pacific
Revenue recognition
Total revenue									2,252	1,783
Service and other revenue
Revenue recognition
Total revenue	5,498	6,552	6,317	5,762	4,302	$ 4,207	$ 4,760	$ 2,790	24,129	16,059	12,117
Service and other revenue | NA
Revenue recognition
Total revenue									18,882	12,809
Service and other revenue | EMEA
Revenue recognition
Total revenue									4,203	2,592
Service and other revenue | Asia Pacific
Revenue recognition
Total revenue									1,044	658
Service-type warranties
Revenue recognition
Total revenue									4,921	4,633
Service-type warranties | NA
Revenue recognition
Total revenue									3,171	3,139
Service-type warranties | EMEA
Revenue recognition
Total revenue									1,543	1,323
Service-type warranties | Asia Pacific
Revenue recognition
Total revenue									207	171
Research services
Revenue recognition
Total revenue									17,973	10,005
Research services | NA
Revenue recognition
Total revenue									15,011	8,845
Research services | EMEA
Revenue recognition
Total revenue									2,225	704
Research services | Asia Pacific
Revenue recognition
Total revenue									737	456
Other services
Revenue recognition
Total revenue									1,235	1,421
Other services | NA
Revenue recognition
Total revenue									700	825
Other services | EMEA
Revenue recognition
Total revenue									435	565
Other services | Asia Pacific
Revenue recognition
Total revenue									100	31
Collaboration and license revenue
Revenue recognition
Total revenue	408	11,246	$ 23	$ 132	$ 184				11,809	184	$ 2,150
Collaboration and license revenue | NA
Revenue recognition
Total revenue									11,685	167
Collaboration and license revenue | EMEA
Revenue recognition
Total revenue									124	$ 17
Grant revenue
Revenue recognition
Total revenue	$ 4,493	$ 1,929							$ 6,422

Significant accounting polici_6

Significant accounting policies - Future performance obligations (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)
Transaction Price Allocated to Future Performance Obligations
Amount of transaction price allocated to performance obligations	$ 6
Previously deferred revenue	1.2
Service-type warranties and research services
Transaction Price Allocated to Future Performance Obligations
Amount of transaction price allocated to performance obligations	4.9
Undelivered licenses of intellectual property
Transaction Price Allocated to Future Performance Obligations
Amount of transaction price allocated to performance obligations	0.5
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Transaction Price Allocated to Future Performance Obligations
Amount of transaction price allocated to performance obligations	$ 5.4
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	12 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Transaction Price Allocated to Future Performance Obligations
Amount of transaction price allocated to performance obligations	$ 0.6
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	24 months

Significant accounting polici_7

Significant accounting policies - Changes in deferred revenue from contracts with customers (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)
Changes in deferred revenue from contracts with customers
Balance at beginning of period	$ 5,163
Deferral of revenue	6,955
Recognition of deferred revenue	(6,120)
Balance at end of period	$ 5,998

Significant accounting polici_8

Significant accounting policies - Costs to obtain a contract (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)
Change in the balance of costs to obtain a contract
Balance at beginning of period	$ 335
Deferral of costs to obtain a contract	506
Recognition of costs to obtain a contract	(593)
Balance at end of period	$ 248

Significant accounting polici_9

Significant accounting policies - Practical expedients (Details)	12 Months Ended
	Dec. 31, 2020
Revenue recognition
Revenue, Practical Expedient, Financing Component [true false]	true
Revenue, Remaining Performance Obligation, Optional Exemption, Performance Obligation [true false]	true

Significant accounting polic_10

Significant accounting policies - Grant revenue (Details) - USD ($) $ in Thousands	Sep. 29, 2020	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Total revenue		$ 26,131	$ 31,389	$ 13,130	$ 15,727	$ 15,917	$ 14,944	$ 13,536	$ 12,337	$ 86,377	$ 56,734	$ 37,632
Research and Development Expense		6,217	5,377	$ 4,312	$ 4,268	$ 4,398	$ 3,924	$ 4,016	$ 3,852	20,174	$ 16,190	$ 15,805
RADx WP1
Research and Development Expense										1,000
RADx WP2
Contract value	$ 18,200
Research and Development Expense										2,600
Grant revenue
Total revenue		$ 4,493	$ 1,929							6,422
Grant revenue | RADx WP1
Total revenue										2,000
Grant revenue | RADx WP2
Total revenue										4,362
Contract value										$ 18,200

Significant accounting polic_11

Significant accounting policies - Summarizes the activity under WP2 (Details) - USD ($) $ in Thousands	Sep. 29, 2020	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Total revenue		$ 26,131	$ 31,389	$ 13,130	$ 15,727	$ 15,917	$ 14,944	$ 13,536	$ 12,337	$ 86,377	$ 56,734	$ 37,632
Grant revenue
Disaggregation of Revenue [Line Items]
Total revenue		4,493	$ 1,929							6,422
RADx WP2
Disaggregation of Revenue [Line Items]
Total WP2 grant amount	$ 18,200
RADx WP2 | Grant revenue
Disaggregation of Revenue [Line Items]
Total revenue										4,362
Total proceeds used for assets										826
Total deferred proceeds for assets										2,478
Total deferred grant revenue										304
Total recognized										7,970
Total amount accrued		(2,968)								(2,968)
Total cash received										5,002
Total proceeds received										5,002
Total proceeds reasonably assured		$ 13,198								13,198
Total WP2 grant amount										$ 18,200

Significant accounting polic_12

Significant accounting policies - Net loss per share (Details) - shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Outstanding potentially dilutive securities that have been excluded in the calculation of diluted net loss per share
Number of dilutive securities excluded in the calculation of diluted net loss per share	3,022,432	2,926,991	2,914,420
Unvested restricted common stock and restricted stock units
Outstanding potentially dilutive securities that have been excluded in the calculation of diluted net loss per share
Number of dilutive securities excluded in the calculation of diluted net loss per share	518,387	409,929	361,468
Outstanding stock options
Outstanding potentially dilutive securities that have been excluded in the calculation of diluted net loss per share
Number of dilutive securities excluded in the calculation of diluted net loss per share	2,494,045	2,507,062	2,476,911
Common stock
Outstanding potentially dilutive securities that have been excluded in the calculation of diluted net loss per share
Number of dilutive securities excluded in the calculation of diluted net loss per share	10,000	10,000	76,041
Obligation to issue warrants, in shares	93,341	93,341	93,341

Significant accounting polic_13

Significant accounting policies - Cash and Cash equivalents and Restricted cash and deposits (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash and Cash equivalents
Cash	$ 19,535	$ 6,406
Money Market funds invested in U.S. Treasury obligations	162,049	102,749
Cash and cash equivalents	181,584	109,155	$ 44,429
Restricted cash and deposits
Restricted cash and deposits	1,100	1,100
Restricted cash, current	1,000	1,100
Restricted cash	1,000	1,026	$ 1,000
Other noncurrent assets
Restricted cash and deposits
Restricted cash and deposits	$ 100	$ 100

Significant accounting polic_14

Significant accounting policies - Allowance for doubtful accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	$ 162	$ 36
Additions	493	160	$ 36
Deductions	(285)	(34)
Ending Balance	$ 370	$ 162	$ 36

Significant accounting polic_15

Significant accounting policies - Property and equipment (Details)	12 Months Ended
	Dec. 31, 2020
Laboratory and manufacturing equipment
Property and equipment
Estimated useful life (in years)	5 years
Computers and software
Property and equipment
Estimated useful life (in years)	3 years
Office furniture and equipment
Property and equipment
Estimated useful life (in years)	7 years

Significant accounting polic_16

Significant accounting policies - Fair value of financial instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Fair value of financial instruments
Cash equivalents	$ 162,048	$ 102,749
Total	162,048	102,749
Level 1
Fair value of financial instruments
Cash equivalents	162,048	102,749
Total	$ 162,048	$ 102,749

Significant accounting polic_17

Significant accounting policies - Warranties (Details)	12 Months Ended
	Dec. 31, 2020
Significant accounting policies
Warranty period (in years)	1 year

Significant accounting polic_18

Significant accounting policies - Credit, product and supplier concentrations and off-balance-sheet risk (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accounts Receivable Concentration
Concentration Risk
Concentration risk (in percent)	29.00%	50.00%
Revenue Concentration
Concentration Risk
Concentration risk (in percent)	10.00%	10.00%
Revenue Concentration | One customer
Concentration Risk
Percentage of aggregate accounts receivable accounted by one customer	13.00%
Customer Concentration Risk | One customer
Concentration Risk
Concentration risk (in percent)		10.00%	10.00%
Percentage of aggregate accounts receivable accounted by one customer	19.00%

Significant accounting polic_19

Significant accounting policies - Stock-based compensation (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jan. 01, 2019
New Accounting Pronouncement, Early Adoption
Expected dividend yield	0.00%	0.00%	0.00%
Expected term (in years)	6 years	6 years	5 years 10 months 24 days
Weighted-average fair value of options granted	$ 12.66	$ 9.09	$ 7.19
Accumulated deficit	$ (247,774)	$ (216,244)	$ (175,888)	$ (175,448)
Minimum
New Accounting Pronouncement, Early Adoption
Risk-free interest rate	0.40%	1.40%	2.60%
Expected volatility	43.90%	33.50%	32.40%
Maximum
New Accounting Pronouncement, Early Adoption
Risk-free interest rate	1.70%	2.60%	3.00%
Expected volatility	49.20%	39.70%	36.80%

Significant accounting polic_20

Significant accounting policies - Right of use assets (Details) $ in Thousands	Dec. 31, 2020USD ($)
Impact on consolidated balance sheet and statement of operations, as a result of adopting ASU 842
Operating Lease, Right-of-Use Asset	$ 11,995
Operating Lease, Liability, Noncurrent	21,891
Restatement adjustment | ASU 2016-02
Impact on consolidated balance sheet and statement of operations, as a result of adopting ASU 842
Operating Lease, Right-of-Use Asset	12,200
Operating Lease, Liability, Noncurrent	$ 22,800

Significant accounting polic_21

Significant accounting policies - Recent accounting pronouncements (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jan. 01, 2019
Assets [Abstract]
Accounts receivable	$ 17,184				$ 10,906				$ 17,184	$ 10,906	$ 6,792	$ 6,839
Prepaid expenses and other current assets	5,981				2,137				5,981	2,137	2,330	2,618
Other non-current assets					557					557	536	555
Liabilities [Abstract]
Deferred revenue	5,421				4,697				5,421	4,697	5,437	5,394
Deferred revenue, net of current portion	577				466				577	466	520	477
Stockholders' Equity Attributable to Parent [Abstract]
Accumulated deficit	(247,774)				(216,244)				(247,774)	(216,244)	(175,888)	(175,448)
Total revenue	26,131	$ 31,389	$ 13,130	$ 15,727	15,917	$ 14,944	$ 13,536	$ 12,337	86,377	56,734	37,632
Total costs of goods sold, services, and licenses	11,081	10,283	7,917	8,914	9,052	7,911	6,605	6,330	38,195	29,898	19,684
Gross Profit	15,050	21,106	5,213	6,813	6,865	7,033	6,931	6,007	48,182	26,836	17,948
Selling, General and Administrative Expense	18,766	13,451	13,102	14,273	13,953	13,352	13,429	11,512	59,592	52,246	33,693
Net income	(9,821)	2,203	(12,302)	(11,610)	(10,958)	(9,870)	(10,563)	(9,405)	(31,530)	(40,796)	(31,536)
Restricted cash	1,000				1,026				1,000	1,026	1,000
Adjustments
Assets [Abstract]
Accounts receivable											47
Prepaid expenses and other current assets					335					335	288
Other non-current assets											19
Liabilities [Abstract]
Deferred revenue					(209)					(209)	43
Deferred revenue, net of current portion					14					14	43
Stockholders' Equity Attributable to Parent [Abstract]
Accumulated deficit					(140)					(140)	(440)	$ 400
Total costs of goods sold, services, and licenses										1
Gross Profit										327
Selling, General and Administrative Expense										27
Net income										300
Balances without adoption of ASU 606
Assets [Abstract]
Accounts receivable					10,906					10,906
Prepaid expenses and other current assets					1,802					1,802
Other non-current assets					557					557
Liabilities [Abstract]
Deferred revenue					4,488					4,488
Deferred revenue, net of current portion					480					480
Stockholders' Equity Attributable to Parent [Abstract]
Accumulated deficit					(216,104)					(216,104)
Total costs of goods sold, services, and licenses										29,899
Gross Profit										27,163
Selling, General and Administrative Expense										52,273
Net income										(40,496)
Product revenue
Stockholders' Equity Attributable to Parent [Abstract]
Total revenue	15,732	11,662	6,790	9,833	11,431	10,737	8,776	9,547	44,017	40,491	23,365
Total costs of goods sold, services, and licenses	7,961	6,387	5,416	6,186	6,684	5,513	4,455	4,248	25,950	20,900	12,729
Product revenue | Adjustments
Stockholders' Equity Attributable to Parent [Abstract]
Total revenue										55
Product revenue | Balances without adoption of ASU 606
Stockholders' Equity Attributable to Parent [Abstract]
Total revenue										40,546
Service and other revenue
Stockholders' Equity Attributable to Parent [Abstract]
Total revenue	5,498	6,552	6,317	5,762	4,302	4,207	4,760	2,790	24,129	16,059	12,117
Total costs of goods sold, services, and licenses	$ 3,120	$ 2,896	$ 2,501	$ 2,728	$ 2,368	$ 2,398	$ 2,150	$ 2,082	$ 11,245	8,998	$ 6,955
Service and other revenue | Adjustments
Stockholders' Equity Attributable to Parent [Abstract]
Total revenue										273
Service and other revenue | Balances without adoption of ASU 606
Stockholders' Equity Attributable to Parent [Abstract]
Total revenue										$ 16,332

Inventory (Details)

Inventory (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Inventory
Raw Materials	$ 5,265	$ 4,717
Work in process	3,306	2,573
Finished goods	6,285	3,173
Total	$ 14,856	$ 10,463

Property and equipment (Details

Property and equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Property and equipment
Property and equipment, gross	$ 20,348	$ 16,386
Less: accumulated depreciation	(6,436)	(4,339)
Total	13,912	12,047
Depreciation expense	2,200	1,600
Laboratory and manufacturing equipment
Property and equipment
Property and equipment, gross	8,523	5,391
Laboratory and manufacturing instruments used internally
Property and equipment
Property and equipment, gross	3,400	2,800
Less: accumulated depreciation	(1,800)	(1,200)
Office furniture and equipment
Property and equipment
Property and equipment, gross	1,556	1,403
Computers and software
Property and equipment
Property and equipment, gross	1,504	1,103
Leasehold improvements
Property and equipment
Property and equipment, gross	$ 8,765	$ 8,489

Other accrued expenses (Details

Other accrued expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Other accrued expenses
Accrued inventory purchases	$ 527	$ 459
Accrued royalties	1,845	476
Accrued professional services	797	655
Accrued development costs	323	151
Accrued other	1,353	757
Total accrued expenses	$ 4,845	$ 2,498

Other accrued expenses - Other

Other accrued expenses - Other non-current liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Other non-current liabilities
Leasehold obligation incentive		$ 7,572
Deferred Rent		3,009
Deferred tax liabilities	$ 2,649	2,825
Other		1
Total non-current liabilities	$ 2,649	$ 13,407

Income taxes - Components of in

Income taxes - Components of income (loss) before income taxes (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Components of income (loss) before income taxes
United States									$ (29,896)	$ (40,010)	$ (31,436)
Foreign									(2,010)	(973)	(75)
Loss before income taxes	$ (9,944)	$ 2,092	$ (12,320)	$ (11,734)	$ (11,065)	$ (9,995)	$ (10,540)	$ (9,383)	$ (31,906)	$ (40,983)	$ (31,511)

Income taxes - Provision for (b

Income taxes - Provision for (benefit from) income taxes (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current:
State									$ (13)	$ (20)	$ (18)
Foreign									(102)	(93)
Total current income tax provision									(115)	(113)	(18)
Deferred
Federal									(8)	(3)	(2)
State									(3)	(1)	(5)
Foreign									502	304
Total deferred income tax benefit (provision)									491	300	(7)
Total income tax benefit (provision)	$ 123	$ 111	$ 18	$ 124	$ 107	$ 125	$ (23)	$ (22)	$ 376	$ 187	$ (25)

Income taxes - Reconciliation o

Income taxes - Reconciliation of the federal statutory income tax rate to the effective tax rate (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Taxes
Taxable goodwill or intangible assets	$ 49,000	$ 31,000
Reconciliation of the federal statutory income tax rate to the effective tax rate
Federal statutory income tax rate (in percent)	21.00%	21.00%	21.00%
Foreign tax rate differential (in percent)	0.30%
State taxes, net of federal benefit (in percent)	2.50%	3.20%	6.00%
Tax credits (in percent)	1.60%	2.30%	2.70%
Share-based compensation (in percent)	5.20%	2.30%	1.10%
Permanent items (in percent)	(0.40%)	(0.90%)	(1.20%)
Deferred tax rate change (in percent)	0.30%	(1.40%)
Change in valuation allowance (in percent)	(29.70%)	(24.60%)	(29.90%)
Other (in percent)	0.40%	(1.40%)	0.20%
Effective income tax rate (in percent)	1.20%	0.50%	(0.10%)
Tax due at international rate (in percent)	1.20%
Impact of Acquisition (in percent)	21.00%
Aushon acquisition
Income Taxes
Amortizable goodwill		$ 300,000
UmanDiagnostics AB Acquisition
Income Taxes
Taxable goodwill or intangible assets	$ 0

Income taxes - Deferred tax ass

Income taxes - Deferred tax assets and liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
NOLs	$ 50,233	$ 43,814
Tax Credits	5,101	5,518
Deferred revenue	2,167	1,247
Amortization	1,054	928
Stock-based compensation	1,956	973
Deferred rent		727
Lease incentive obligation		1,828
Lease liability	5,703
Other deferred tax assets	2,533	1,325
Total deferred tax assets	68,747	56,360
Valuation allowance	(63,609)	(54,137)	$ (44,033)
Net Deferred tax assets	5,138	2,223
Right of use asset	(2,957)
Depreciation	(1,775)	(1,769)
Amortization of acquired intangibles	(2,880)	(3,031)
Inventory	(64)	(212)
Goodwill	(49)	(31)
Other deferred tax liabilities	(61)	(5)
Net deferred tax assets (liability)	$ 2,648	$ 2,825

Income taxes - Valuation allowa

Income taxes - Valuation allowance deferred tax (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Income taxes
Balance, beginning of year	$ 54,137	$ 44,033
Change in valuation allowance	9,472	10,104
Balance, end of year	$ 63,609	$ 54,137

Income taxes (Details)

Income taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Taxes
Valuation allowance	$ 63,609	$ 54,137	$ 44,033
Increase (decrease) in Valuation allowance	9,472	10,104
Net operating loss (NOL) carryforwards	$ 199,300
Tax credit carryforwards			4,500
Cumulative change in ownership related to percentage points	5.00%
Percentage Points Related To Ownership Change	50.00%
Rolling Period Duration Of Ownership Change	3 years
Accrued interest or penalties	$ 0	0	0
Federal
Income Taxes
Operating Loss Carryforwards, Subject To Expiry			108,500
Operating Loss Carryforwards, Not Subject To Expiry			$ 90,800
Federal | Through Tax Year 2039 [Member]
Income Taxes
Tax credit carryforwards	4,500
State
Income Taxes
Tax credit carryforwards	$ 800
State | Through Tax Year 2039 [Member]
Income Taxes
Net operating loss (NOL) carryforwards		$ 133,700

Common Stock, warrants, stock_3

Common Stock, warrants, stock-based compensation, stock options, restricted stock and restricted stock units- Common stock reserved (Details) - shares	Dec. 31, 2020	Dec. 31, 2019
Warrants, stock-based compensation, stock options, restricted stock and restricted stock units
Shares reserved for future awards under compensation plan	1,559,108	882,715
Common stock reserved	4,581,540	3,809,706
Outstanding warrants
Warrants, stock-based compensation, stock options, restricted stock and restricted stock units
Common stock reserved	10,000	10,000
Common stock options and unvested restricted common stock
Warrants, stock-based compensation, stock options, restricted stock and restricted stock units
Common stock reserved	3,012,432	2,916,991

Common Stock, warrants, stock_4

Common Stock, warrants, stock-based compensation, stock options, restricted stock and restricted stock units- Warrants (Details) - $ / shares	Jul. 02, 2019	Jan. 30, 2018	Dec. 31, 2020
Number outstanding
Issued (in shares)		10,000
Weighted Average Exercise Price
Warrants And Rights, Exercised	66,041
Exercise of common stock warrants (in shares)	45,690
Outstanding warrants
Number outstanding
Outstanding at the beginning of the period (in shares)			10,000
Issued (in shares)
Exercised (in shares)
Cancelled (in shares)
Outstanding at the end of the period (in shares)			10,000
Weighted Average Exercise Price
Outstanding at the beginning of the period (in dollars per share)			$ 21
Issued (in dollars per share)
Exercised (in dollars per share)
Cancelled (in dollars per share)
Outstanding at the end of the period (in dollars per share)			$ 21
Obligation To Issue Warrants, In Shares			93,341
Shares reserved related to potential obligations to issue warrants in the future			0

Common Stock, warrants, stock_5

Common Stock, warrants, stock-based compensation, stock options, restricted stock and restricted stock units - Share-based compensation expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Warrants, stock-based compensation, stock options, restricted stock and restricted stock units
Share-based compensation expense	$ 10,099	$ 6,388	$ 4,884
Cost of product revenue
Warrants, stock-based compensation, stock options, restricted stock and restricted stock units
Share-based compensation expense	189	86	55
Cost of service and other revenue
Warrants, stock-based compensation, stock options, restricted stock and restricted stock units
Share-based compensation expense	311	238	173
Research and development
Warrants, stock-based compensation, stock options, restricted stock and restricted stock units
Share-based compensation expense	1,129	718	513
General and administrative
Warrants, stock-based compensation, stock options, restricted stock and restricted stock units
Share-based compensation expense	$ 8,470	$ 5,346	$ 4,143

Common Stock, warrants, stock_6

Common Stock, warrants, stock-based compensation, stock options, restricted stock and restricted stock units - Stock-based award plans (Details) - shares	Jan. 01, 2021	Jan. 01, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2017
Warrants, stock-based compensation, stock options, restricted stock and restricted stock units
Common stock available for future awards (in shares)			4,581,540	3,809,706
2007 Plan
Warrants, stock-based compensation, stock options, restricted stock and restricted stock units
Shares available for grant under the plan (in shares)			0
Annual increase in the shares available for grant under the plan (as a percent of shares of common stock outstanding)			4.00%
2017 Plan
Warrants, stock-based compensation, stock options, restricted stock and restricted stock units
Shares authorized under the plan (in shares)					1,042,314
Additional shares authorized		1,273,501
Shares available for grant under the plan (in shares)			710,839	270,143
Increase in the shares available for grant under the plan (in shares)	318,375
2017 ESPP
Warrants, stock-based compensation, stock options, restricted stock and restricted stock units
Shares authorized under the plan (in shares)				612,572
Shares available for grant under the plan (in shares)			848,269
Annual increase in the shares available for grant under the plan (as a percent of shares of common stock outstanding)				1.00%
Outstanding stock options
Warrants, stock-based compensation, stock options, restricted stock and restricted stock units
Options outstanding (in shares)			2,494,045	2,507,062
Outstanding stock options | 2007 Plan
Warrants, stock-based compensation, stock options, restricted stock and restricted stock units
Options outstanding (in shares)			926,615
Shares authorized under the plan (in shares)					2,490,290

Common Stock, warrants, stock_7

Common Stock, warrants, stock-based compensation, stock options, restricted stock and restricted stock units - Stock options (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Aggregate intrinsic value
Weighted-average fair value of options granted	$ 12.66	$ 9.09	$ 7.19
Share-based compensation expense	$ 10,099	$ 6,388	$ 4,884
Selling, general and administrative expenses
Aggregate intrinsic value
Share-based compensation expense	$ 500
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)	2,507,062
Granted (in shares)	550,290
Exercised (in shares)	(407,687)
Cancelled or forfeited (in shares)	(155,620)
Outstanding at the end of the period (in shares)	2,494,045	2,507,062
Vested and expected to vest at the end of the period (in shares)	2,494,045
Exercisable at the end of the period (in shares)	1,514,576
Weighted-average exercise price
Outstanding at the beginning of the period (in dollars per share)	$ 14.41
Granted (in dollars per share)	28.39
Exercised (in dollars per share)	9.85
Cancelled or forfeited (in dollars per share)	22.58
Outstanding at the end of the period (in dollars per share)	17.73	$ 14.41
Vested and expected to vest at the end of the period (in dollars per share)	17.73
Exercisable at the end of the period (in dollars per share)	$ 12.54
Remaining contractual life
Outstanding (in years)	7 years 3 months 7 days	7 years 6 months 29 days
Vested and expected to vest at the end of the period (in years)	7 years 3 months 7 days
Exercisable at the end of the period (in years)	6 years 5 months 1 day
Aggregate intrinsic value
Outstanding at the beginning of the period	$ 24,870
Exercised	10,400	$ 6,900	5,300
Outstanding at the end of the period	71,760	$ 24,870
Vested and expected to vest at the end of the period	71,760
Exercisable at the end of the period	$ 51,430
Weighted-average fair value of options granted	$ 12.64	$ 9.09
Share-based compensation expense	$ 5,400	$ 3,700	2,700
Intrinsic value of stock options exercised	10,400	$ 6,900	$ 5,300
Total unrecognized compensation cost related to unvested stock options	$ 9,300
Period of recognition of unrecognized compensation cost	7 years 3 months 18 days
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%

Common Stock, warrants, stock_8

Common Stock, warrants, stock-based compensation, stock options, restricted stock and restricted stock units - Restricted stock (Details) - Restricted stock - shares	1 Months Ended		12 Months Ended
	Jan. 31, 2015	Dec. 31, 2014	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)			0	0	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%

Common Stock, warrants, stock_9

Common Stock, warrants, stock-based compensation, stock options, restricted stock and restricted stock units - Restricted stock units (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Weighted-average grant date fair value per share
Share-based compensation expense	$ 10,099	$ 6,388	$ 4,884
Restricted stock units
Number of restricted stock units
Unvested restricted common stock at the beginning of the period (in shares)	370,123
Granted (in shares)	334,665
Vested (in shares)	(182,036)
Cancelled (in shares)	(44,171)
Unvested restricted common stock at the end of the period (in shares)	478,581	370,123
Weighted-average grant date fair value per share
Unvested restricted common stock at the beginning of the period (in dollars per share)	$ 20.48
Granted (in dollars per share)	31.99
Vested (in dollars per share)	20.13
Cancelled (in dollars per share)	26.79
Unvested restricted common stock at the end of the period (in dollars per share)	$ 28.08	$ 20.48
Share-based compensation expense	$ 4,200
Total unrecognized compensation cost related to unvested stock awards	$ 12,000
Period of recognition of unrecognized compensation cost	2 years 9 months 18 days
Restricted stock
Number of restricted stock units
Granted (in shares)	0	0	0
Unvested restricted common stock at the end of the period (in shares)	39,806
Weighted-average grant date fair value per share
Unvested restricted common stock at the end of the period (in dollars per share)	$ 3.12
Share-based compensation expense	$ 0	$ 0	$ 400
Total unrecognized compensation cost related to unvested stock awards	0
Aggregate fair value of restricted stock awards	$ 0	$ 0	$ 2,400
2017 Plan | Restricted stock units
Number of restricted stock units
Granted (in shares)	334,665
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]
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)	268,694
2017 Plan | Restricted stock units | Vesting on December 31, 2020
Number of restricted stock units
Granted (in shares)	15,890
2017 Plan | Restricted stock units | Vested in equal amounts annually over three years
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period 1	3 years
Number of restricted stock units
Granted (in shares)	40,045
2017 Plan | Restricted stock units | Vested on May 31, 2020
Number of restricted stock units
Granted (in shares)	8,576
2017 Plan | Restricted stock units | Vest on May 31, 2021
Number of restricted stock units
Granted (in shares)	1,460

Leases (Details)

Leases (Details) $ in Thousands	Apr. 01, 2019USD ($)itemft²	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Jan. 01, 2020USD ($)
Operating Lease, Right-of-Use Asset		$ 11,995
Operating Lease, Liability, Noncurrent		21,891
Rent expense		4,800
Rent expense			$ 3,300	$ 1,600
Lease for facilities in Billerica, Massachusetts
Term of operating lease	137 months
Square footage of office and laboratory space | ft²	92,000
Drawing capacity	$ 1,000
Landlord Contribution Towards Tenant Improvements	$ 8,200
Lease Agreement Number Of Options To Extend | item	2
Lease Agreement Lease Extension Term	5 years
Operating Lease, Right-of-Use Asset					$ 12,200
Operating Lease, Liability, Noncurrent					22,700
Deferred rent expense		3,000
Lease Obligation Incentive		$ 7,600
Tristeyagen Umea Lease [Member] | Maximum
Operating Lease, Right-of-Use Asset					100
Operating Lease, Liability, Noncurrent					$ 100

Leases - Lease costs recognized

Leases - Lease costs recognized (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)
Lease Costs
Operating lease costs	$ 2,663
Total lease cost	2,663
Operating cash flows used for operating leases	$ 2,108
Weighted average remaining lease term	9 years 9 months 18 days
Weighted average discount rate	9.73%

Leases - Future minimum commitm

Leases - Future minimum commitments (Details) $ in Thousands	Dec. 31, 2020USD ($)
Leases
2021	$ 3,388
2022	3,466
2023	3,515
2024	3,577
2025 and thereafter	22,203
Total lease payments	36,149
Less: imputed interest	13,024
Operating Lease, Liability	$ 23,125

Commitments and contingencies -

Commitments and contingencies - License agreements and Lease commitments (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
License agreements
Cost of revenue	$ 11,081,000	$ 10,283,000	$ 7,917,000	$ 8,914,000	$ 9,052,000	$ 7,911,000	$ 6,605,000	$ 6,330,000	$ 38,195,000	$ 29,898,000	$ 19,684,000
Letter of credit will be reduced at 41 months after the commencement date	750,000								750,000
Letter of credit will be reduced at 65 months after the commencement date	250,000								250,000
Rent expense										3,300,000	1,600,000
Other licenses
License agreements
Royalty expense									0	800,000	400,000
Annual minimum royalty to be paid under the license agreement	$ 50,000								50,000
Tufts | License agreements
License agreements
Royalty expense									1,100,000	$ 1,000,000	$ 700,000
Collaboration and license revenue
License agreements
Cost of revenue		$ 1,000,000							1,000,000
Collaboration and license revenue | Tufts
License agreements
Cost of revenue									$ 1,000,000

Commitments and contingencies_2

Commitments and contingencies - Development and supply agreement and Legal contingencies (Details) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)$ / sharesshares
Commitments and contingencies
Amount payable to counterparty | $	$ 11.7
Period to purchase minimum number of commercial units	7 years
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)

Notes payable (Details) $ in Thousands	Mar. 02, 2020USD ($)	Apr. 15, 2019installment	Apr. 14, 2014	Aug. 31, 2018USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Oct. 31, 2018USD ($)
Long Term Debt
End Of Term Fee					$ 50,000
Loan principal payment installment | installment		4
Non-cash interest expense					100	$ 100	$ 200
Loan agreement
Long Term Debt
Additional amounts available to borrow					$ 0	$ 0
Loan agreement | Minimum
Long Term Debt
Interest rate (as a percent)			8.00%
Amendment 5 to loan agreement
Long Term Debt
Term fee	$ 100			$ 80
Cost incurred upon execution				$ 50
Amendment 6 to loan agreement
Long Term Debt
Certificate of deposit associated with the lease								$ 1,000
Prime rate | Loan agreement
Long Term Debt
Margin on variable interest rate (as a percent)			(5.25%)

Notes payable - Debt payment ob

Notes payable - Debt payment obligations (Details) $ in Thousands	Dec. 31, 2020USD ($)
Debt payment obligations due based on principal payments
2021	$ 7,688
Debt payment obligations	$ 7,688

At-the-market offering (Details

At-the-market offering (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions	Aug. 08, 2019	Jun. 05, 2019	Dec. 31, 2019	Dec. 31, 2020	Mar. 19, 2019
Common stock, aggregate offering price			$ 28	$ 32
Sale of common stock (in shares)	2.7
At-the-market offering
Sale of common stock (in shares)		2.2
Shares issued price (in dollars per share)		$ 22.73
Gross proceeds		$ 49,700
Stock issuance cost		1,700
Sale of common stock in at-the-market offering, net		$ 48,000	$ 48,019
At-the-market offering | Maximum
Common stock, aggregate offering price					$ 50,000

Underwritten public offerings (

Underwritten public offerings (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions	Aug. 06, 2020	Aug. 08, 2019	Aug. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Subsidiary or Equity Method Investee [Line Items]
Stock Issued During Period, Shares, New Issues		2.7
Common stock, par value				$ 0.001	$ 0.001
Underwritten public offering
Subsidiary or Equity Method Investee [Line Items]
Stock Issued During Period, Shares, New Issues	3	2.7	3
Common stock, par value	$ 0.001	$ 0.001	$ 0.001
Gross proceeds	$ 97,600	$ 69,000	$ 97,600
Stock issuance cost	6,200	4,500	6,200
Proceeds from sale of common stock, net of issuance costs	$ 91,400	$ 64,500	$ 91,400	$ 91,404	$ 64,529

Collaboration and license arr_2

Collaboration and license arrangements (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended			24 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2020
Collaboration and license arrangements
Revenue	$ 26,131	$ 31,389	$ 13,130	$ 15,727	$ 15,917	$ 14,944	$ 13,536	$ 12,337	$ 86,377	$ 56,734	$ 37,632
Previously deferred revenue									1,200
Deferred revenue	500				1,700				$ 500	1,700		$ 500
Joint development and license agreement | Maximum
Collaboration and license arrangements
Revenue												$ 100
Abbot license agreement
Collaboration and license arrangements
Number of days notice to terminate agreement									60 days
Initial license fee receivable									$ 10,000
Collaboration and license revenue
Collaboration and license arrangements
Revenue	$ 408	$ 11,246	$ 23	$ 132	$ 184				11,809	$ 184	$ 2,150
Collaboration and license revenue | Abbot license agreement
Collaboration and license arrangements
Revenue									$ 10,000

Employee benefit plans (Details

Employee benefit plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Employee benefit plans
Contribution made to the 401 (k) Plan	$ 0.7	$ 0.5	$ 0.1

Business combinations (Details)

Business combinations (Details) - USD ($) $ in Thousands	Aug. 01, 2019	Jan. 30, 2018	Jul. 31, 2018	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jul. 01, 2019
Fair value of consideration transferred:
Common stock shares consideration				191,152									191,152
Purchase price, net														$ 14,529	$ 3,801
Assets (liabilities) acquired:
Goodwill				$ 10,460				$ 9,353				$ 9,353	$ 10,460	9,353
Total revenue				26,131	$ 31,389	$ 13,130	$ 15,727	15,917	$ 14,944	$ 13,536	$ 12,337		86,377	56,734	37,632
Net loss				$ (9,821)	$ 2,203	$ (12,302)	$ (11,610)	$ (10,958)	$ (9,870)	$ (10,563)	$ (9,405)		(31,530)	(40,796)	(31,536)
Revenue (unaudited)														57,597	38,753
Pre-tax loss (unaudited)														(38,636)	(33,894)
Aushon acquisition
Fair value of consideration transferred:
Cash and cash equivalents acquired		$ 199
Cash		3,200
Obligation to issue cash		800	$ 800
Purchase price, net		4,000
Assets (liabilities) acquired:
Accounts receivable		210
Inventory		828
Prepaids and other current assets		71
Property and equipment and other non-current assets		180
Intangibles		2,950
Goodwill		1,308
Total assets acquired		5,746
Contractual obligations		(1,155)
Accounts payable and accrued liabilities		(591)
Total		$ 4,000
Risk-adjusted discount rate used to determine fair value of intangible assets		14.40%
Transaction costs															$ 100
UmanDiagnostics AB Acquisition
Fair value of consideration transferred:
Common stock shares consideration	191,152
Common stock	$ 5,500
Capital stock shares outstanding, percent	95.00%															5.00%
Cash and stock paid	$ 21,217
Cash and cash equivalents acquired	1,221
Cash	15,700
Purchase price, net	19,996
Assets (liabilities) acquired:
Accounts receivable	638
Inventory	1,680
Prepaids and other current assets	114
Property and equipment	33
Intangibles	13,450
Goodwill	8,111
Accounts payable	(20)
Accrued expense and other current liabilities	(871)
Deferred tax liabilities	(3,139)
Total	$ 19,996
Total revenue												1,100	1,500
Net loss													(100)
Transaction costs													$ 0	$ 1,900
UmanDiagnostics AB Acquisition | Maximum
Assets (liabilities) acquired:
Net loss												$ 100

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Rollforward of goodwill balance
Balance as of beginning of period	$ 9,353
Cumulative translation adjustment	1,107
Balance as of end of period	10,460	$ 9,353
Purchased intangible assets
Gross Carrying Value	16,400	16,400
Accumulated Amortization	(4,101)	(1,991)
Cumulative Translation Adjustment	1,417	(102)
Net Carrying Value	13,716	14,307
Amortization expense	2,100	$ 1,400	$ 600
Estimated amortization expense
2021	2,013
2022	1,930
2023	1,848
2024	1,733
Thereafter	6,192
Estimated Amortization Expenses	$ 13,716
UmanDiagnostics AB Acquisition
Purchased intangible assets
Estimated Useful Life	8 years 4 months 24 days
Goodwill acquired	$ 13,500
Developed technology
Purchased intangible assets
Estimated Useful Life	7 years	7 years
Gross Carrying Value	$ 1,650	$ 1,650
Accumulated Amortization	(1,036)	(737)
Net Carrying Value	$ 614	$ 913
Weighted average life remaining	4 years 1 month 2 days	5 years 1 month 2 days
Customer relationships
Purchased intangible assets
Gross Carrying Value	$ 1,360	$ 1,360
Accumulated Amortization	(618)	(421)
Cumulative Translation Adjustment	12	(1)
Net Carrying Value	$ 754	$ 938
Weighted average life remaining	7 years 29 days	8 years 29 days
Customer relationships | UmanDiagnostics AB Acquisition
Purchased intangible assets
Goodwill acquired	$ 100
Trade names
Purchased intangible assets
Estimated Useful Life	3 years	3 years
Gross Carrying Value	$ 50	$ 50
Accumulated Amortization	(49)	(32)
Net Carrying Value	$ 1	$ 18
Weighted average life remaining	29 days	1 year 1 month 2 days
Know How
Purchased intangible assets
Estimated Useful Life	8 years 6 months	8 years 6 months
Gross Carrying Value	$ 13,000	$ 13,000
Accumulated Amortization	(2,296)	(767)
Cumulative Translation Adjustment	1,374	(99)
Net Carrying Value	$ 12,078	$ 12,134
Weighted average life remaining	6 years 11 months 26 days	8 years
Know How | UmanDiagnostics AB Acquisition
Purchased intangible assets
Goodwill acquired	$ 13,000
Noncompete Agreements
Purchased intangible assets
Estimated Useful Life	5 years 6 months	5 years 6 months
Gross Carrying Value	$ 340	$ 340
Accumulated Amortization	(102)	(34)
Cumulative Translation Adjustment	31	(2)
Net Carrying Value	$ 269	$ 304
Weighted average life remaining	3 years 11 months 26 days	5 years
Noncompete Agreements | UmanDiagnostics AB Acquisition
Purchased intangible assets
Goodwill acquired	$ 400
Maximum | Customer relationships
Purchased intangible assets
Estimated Useful Life	10 years	10 years
Minimum | Customer relationships
Purchased intangible assets
Estimated Useful Life	8 years 6 months	8 years 6 months

Related party transactions (Det

Related party transactions (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Nov. 14, 2019	Nov. 13, 2019	Nov. 28, 2018
Related party transactions
Cost of Revenue	$ 11,081,000	$ 10,283,000	$ 7,917,000	$ 8,914,000	$ 9,052,000	$ 7,911,000	$ 6,605,000	$ 6,330,000	$ 38,195,000	$ 29,898,000	$ 19,684,000
Commitment to sponsor agreement
Collaboration and license revenue
Related party transactions
Related party revenue									0	0	2,150,000
Cost of Revenue		$ 1,000,000							1,000,000
Tufts | Collaboration and license revenue
Related party transactions
Cost of Revenue									1,000,000
Tufts | License Agreement
Related party transactions
Royalty Expense									1,100,000	1,000,000	700,000
Harvard University
Related party transactions
Related party revenue									100,000	100,000
Harvard University | Maximum
Related party transactions
Related party revenue											$ 100,000
PPH | Maximum
Related party transactions
Commitment to sponsor agreement												$ 200,000	$ 120,000	$ 120,000
Total contributions to sponsor agreement	$ 100,000				$ 100,000				$ 100,000	$ 100,000

Restricted Cash (Details)

Restricted Cash (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Restricted Cash
Restricted cash	$ 1,000,000	$ 1,026,000	$ 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

Quarterly Data (Unaudited) (Det

Quarterly Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Total revenue	$ 26,131	$ 31,389	$ 13,130	$ 15,727	$ 15,917	$ 14,944	$ 13,536	$ 12,337	$ 86,377	$ 56,734	$ 37,632
Costs of goods sold:
Total costs of goods sold, services, and licenses	11,081	10,283	7,917	8,914	9,052	7,911	6,605	6,330	38,195	29,898	19,684
Gross profit	15,050	21,106	5,213	6,813	6,865	7,033	6,931	6,007	48,182	26,836	17,948
Operating expenses:
Research and development	6,217	5,377	4,312	4,268	4,398	3,924	4,016	3,852	20,174	16,190	15,805
Selling, general and administrative	18,766	13,451	13,102	14,273	13,953	13,352	13,429	11,512	59,592	52,246	33,693
Total operating expenses	24,983	18,828	17,414	18,541	18,351	17,276	17,445	15,364	79,766	68,436
Loss from operations	(9,933)	2,278	(12,201)	(11,728)	(11,486)	(10,243)	(10,514)	(9,357)	(31,584)	(41,600)	(31,550)
Interest income (expense), net	(166)	(160)	(108)	161	282	282	42	21	(273)	627	46
Other income (expense), net	155	(26)	(11)	(167)	139	(34)	(68)	(47)	(49)	(10)	(7)
Income (loss) before income taxes	(9,944)	2,092	(12,320)	(11,734)	(11,065)	(9,995)	(10,540)	(9,383)	(31,906)	(40,983)	(31,511)
Income tax benefit (provision)	123	111	18	124	107	125	(23)	(22)	376	187	(25)
Net loss	$ (9,821)	$ 2,203	$ (12,302)	$ (11,610)	$ (10,958)	$ (9,870)	$ (10,563)	$ (9,405)	$ (31,530)	$ (40,796)	$ (31,536)
Net loss per share, basic and diluted	$ (0.31)	$ 0.07	$ (0.43)	$ (0.41)	$ (0.39)	$ (0.37)	$ (0.46)	$ (0.42)	$ (1.07)	$ (1.63)	$ (1.43)
Weighted-average common shares outstanding, basic and diluted					28,021,957	26,627,831	23,213,653	22,422,960	29,589,132	25,090,708	21,994,317
Weighted-average common shares outstanding, basic	31,696,002	30,139,157	28,312,925	28,179,132					29,589,132
Net income (loss) per share, diluted	$ (0.31)	$ 0.07	$ (0.43)	$ (0.41)					$ (1.07)
Weighted-average common shares outstanding, diluted	31,696,002	31,386,439	28,312,925	28,179,132					29,589,132
Product revenue
Total revenue	$ 15,732	$ 11,662	$ 6,790	$ 9,833	$ 11,431	$ 10,737	$ 8,776	$ 9,547	$ 44,017	$ 40,491	$ 23,365
Costs of goods sold:
Total costs of goods sold, services, and licenses	7,961	6,387	5,416	6,186	6,684	5,513	4,455	4,248	25,950	20,900	12,729
Service and other revenue
Total revenue	5,498	6,552	6,317	5,762	4,302	4,207	4,760	2,790	24,129	16,059	12,117
Costs of goods sold:
Total costs of goods sold, services, and licenses	3,120	2,896	2,501	2,728	2,368	$ 2,398	$ 2,150	$ 2,082	11,245	8,998	6,955
Collaboration and license revenue
Total revenue	408	11,246	$ 23	$ 132	$ 184				11,809	$ 184	$ 2,150
Costs of goods sold:
Total costs of goods sold, services, and licenses		1,000							1,000
Grant revenue
Total revenue	$ 4,493	$ 1,929							$ 6,422

Subsequent events (Details)

Subsequent events (Details) - USD ($) $ / shares in Units, $ in Millions	Feb. 03, 2021	Aug. 08, 2019	Dec. 31, 2020	Dec. 31, 2019
Subsequent events
Sale of common stock (in shares)		2,700,000
Common stock, par value			$ 0.001	$ 0.001
Subsequent event | Over-Allotment Option
Subsequent events
Sale of common stock (in shares)	4,107,142
Common stock, par value	$ 0.001
Proceeds from sale of common stock, net of issuance costs	$ 287.5
Stock issuance cost	17.9
Net proceeds	$ 269.6