T2 Biosystems (TTOO) 10-K 9 Mar 16 2015 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Mar. 04, 2016	Jun. 30, 2015
Document and Entity Information
Entity Registrant Name	T2 Biosystems, Inc.
Entity Central Index Key	1,492,674
Document Type	10-K
Document Period End Date	Dec. 31, 2015
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Entity Public Float			$ 185.9
Entity Common Stock, Shares Outstanding		24,248,859
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	FY

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 73,662	$ 73,849
Accounts receivable	369	201
Prepaid expenses and other current assets	860	1,076
Inventories	683	115
Current portion of restricted cash		80
Total current assets	75,574	75,321
Property and equipment, net	10,655	2,760
Restricted cash, net of current portion	260	260
Deferred tax assets		313
Other assets	459	480
Total assets	86,948	79,134
Current liabilities:
Accounts payable	1,228	735
Accrued expenses and other current liabilities	4,162	3,662
Current portion of notes payable	4,471	295
Deferred revenue	2,146	80
Deferred tax liabilities		313
Current portion of lease incentives	268	87
Total current liabilities	12,275	5,172
Notes payable, net of current portion	26,222	20,660
Lease incentives, net of current portion	1,076	106
Other liabilities	$ 436	$ 195
Commitments and contingencies (Note 13)
Stockholders' equity:
Preferred stock, $0.001 par value; 10,000,000 shares authorized; no shares issued and outstanding at December 31, 2015 and 2014
Common stock, $0.001 par value; 200,000,000 shares authorized at December 31, 2015 and 2014; 24,175,381 and 20,041,645 shares issued and outstanding at December 31, 2015 and 2014 respectively	$ 24	$ 20
Additional paid-in capital	195,800	156,576
Accumulated deficit	(148,885)	(103,595)
Total stockholders' equity	46,939	53,001
Total liabilities and stockholders' equity	$ 86,948	$ 79,134

Consolidated Balance Sheet (Par

Consolidated Balance Sheet (Parentheticals) - $ / shares	Dec. 31, 2015	Dec. 31, 2014
Consolidated Balance Sheets
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred Stock, Shares Authorized	10,000,000	10,000,000
Preferred Stock, Shares Issued	0	0
Preferred Stock, Shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	24,175,381	20,041,645
Common stock, shares outstanding	24,175,381	20,041,645

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenue:
Product revenue	$ 599
Research revenue	2,214	$ 119	$ 266
Total revenue	2,813	119	266
Costs and expenses:
Cost of product revenue	1,740
Research and development	25,362	19,782	14,936
Selling, general and administrative	19,094	11,018	5,022
Total costs and expenses	46,196	30,800	19,958
Loss from operations	(43,383)	(30,681)	(19,692)
Interest expense, net	(1,967)	(721)	(403)
Other income (expense), net	60	12	(515)
Net loss and comprehensive loss	(45,290)	(31,390)	(20,610)
Accretion of redeemable convertible preferred stock to redemption value		(4,570)	(6,908)
Net loss applicable to common stockholders	$ (45,290)	$ (35,960)	$ (27,518)
Net loss per share applicable to common stockholders - basic and diluted	$ (2.21)	$ (4.15)	$ (19.72)
Weighted-average number of common shares used in computing net loss per share applicable to common stockholders - basic and diluted	20,501,748	8,674,931	1,395,562

Consolidated Statements of Rede

Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders Equity (Deficit) - USD ($) $ in Thousands	Series A-1	Series A-2	Series B	Series C	Series D	Series E	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Total
Balance at Dec. 31, 2012	$ 830	$ 7,322	$ 14,594	$ 17,895	$ 25,496
Balance (in shares) at Dec. 31, 2012	282,849	1,703,959	3,249,877	4,055,125	5,054,945
Increase (Decrease) in Redeemable Convertible Preferred Stock
Issuance of Series E redeemable convertible preferred stock, net of issuance costs of $232						$ 39,768
Issuance of Series E redeemable convertible preferred stock, net of issuance costs of $232 (in shares)						6,930,967
Accretion of redeemable convertible preferred stock to redemption value	$ 44	$ 402	$ 870	$ 1,205	$ 1,861	$ 2,526
Balance at Dec. 31, 2013	$ 874	$ 7,724	$ 15,464	$ 19,100	$ 27,357	$ 42,294
Balance (in shares) at Dec. 31, 2013	282,849	1,703,959	3,249,877	4,055,125	5,054,945	6,930,967
Balance at Dec. 31, 2012							$ 1		$ (62,659)	$ (62,658)
Balance (in shares) at Dec. 31, 2012							1,362,043
Increase (Decrease) in Stockholders' Equity
Accretion of redeemable convertible preferred stock to redemption value								$ (633)	(6,275)	(6,908)
Exercise of stock options								55		55
Exercise of stock options (in shares)							49,943
Stock-based compensation expense								578		578
Net loss									(20,610)	(20,610)
Balance at Dec. 31, 2013							$ 1		(89,544)	(89,543)
Balance (in shares) at Dec. 31, 2013							1,411,986
Increase (Decrease) in Redeemable Convertible Preferred Stock
Accretion of redeemable convertible preferred stock to redemption value	$ 26	$ 240	$ 520	$ 722	$ 1,115	$ 1,947
Conversion of redeemable convertible preferred stock into common stock	$ (900)	$ (7,964)	$ (15,984)	$ (19,822)	$ (28,472)	$ (44,241)
Conversion of redeemable convertible preferred stock into common stock (in shares)	(282,849)	(1,703,959)	(3,249,877)	(4,055,125)	(5,054,945)	(6,930,967)
Increase (Decrease) in Stockholders' Equity
Accretion of redeemable convertible preferred stock to redemption value								(880)	(3,690)	(4,570)
Stock-based compensation expense								1,653		1,653
Conversion of redeemable convertible preferred stock into common stock							$ 13	96,341	21,029	117,383
Conversion of redeemable convertible preferred stock into common stock (in shares)							12,516,298
Issuance of common stock upon net settlement of warrants to purchase redeemable convertible preferred stock								1,226		1,226
Issuance of common stock upon net settlement of warrants to purchase redeemable convertible preferred stock (in shares)							68,700
Issuance of common stock from initial public offering, net of offering costs of $7,700 and $2,732, respectively.							$ 6	58,083		58,089
Issuance of common stock from initial public offering, net of offering costs of $7,700 and $2,732, respectively (in shares)							5,980,000
Exercise of stock options								153		153
Exercise of stock options (in shares)							64,661
Net loss									(31,390)	(31,390)
Balance at Dec. 31, 2014							$ 20	156,576	(103,595)	$ 53,001
Balance (in shares) at Dec. 31, 2014							20,041,645			20,041,645
Increase (Decrease) in Stockholders' Equity
Stock-based compensation expense								4,168		$ 4,168
Issuance of common stock from initial public offering, net of offering costs of $7,700 and $2,732, respectively.							$ 4	33,252		33,256
Issuance of common stock from initial public offering, net of offering costs of $7,700 and $2,732, respectively (in shares)							3,691,049
Issuance of common stock from exercise of stock options and employee stock purchase plan								1,804		1,804
Issuance of common stock from exercises of stock options and employee stock purchase plan (in shares)							442,687
Net loss									(45,290)	(45,290)
Balance at Dec. 31, 2015							$ 24	$ 195,800	$ (148,885)	$ 46,939
Balance (in shares) at Dec. 31, 2015							24,175,381			24,175,381

Consolidated Statements of Red6

Consolidated Statements of Redeemable Convertible Preferred Stock and Stockholders Equity (Deficit) (Parentheticals) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Common Stock
Issuance costs	$ 2,732	$ 7,700
Series E
Issuance costs			$ 232

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating activities
Net loss	$ (45,290)	$ (31,390)	$ (20,610)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	1,465	691	584
Stock-based compensation expense	4,168	1,653	578
Noncash interest expense	354	112	44
Change in fair value of warrants		1	530
Loss on disposal of asset			6
Deferred rent	(119)	5	(5)
Changes in operating assets and liabilities:
Accounts receivable	(168)	(201)
Prepaid expenses and other assets	190	(1,217)	(138)
Inventory	(568)	(115)
Accounts payable	177	(208)	372
Accrued expenses and other liabilities	260	2,405	586
Deferred revenue	2,066	80
Net cash used in operating activities	(37,465)	(28,184)	(18,053)
Investing activities
Purchases of property and equipment	(7,974)	(2,084)	(513)
Decrease in restricted cash	80		80
Net cash used in investing activities	(7,894)	(2,084)	(433)
Financing activities
Proceeds from issuance of common stock in public offering, net of offering costs	33,677	58,089
Proceeds from issuance of redeemable convertible preferred stock, net			39,768
Proceeds from issuance of common stock and stock options exercises, net	1,804	153	55
Proceeds from issuance of note payable, net	10,000	19,714
Repayments of notes payable	(309)	(4,037)	(848)
Net cash provided by financing activities	45,172	73,919	38,975
Net (decrease) increase in cash and cash equivalents	(187)	43,651	20,489
Cash and cash equivalents at beginning of period	73,849	30,198	9,709
Cash and cash equivalents at end of period	73,662	73,849	30,198
Supplemental disclosures of cash flow information
Cash paid for interest	1,506	515	345
Supplemental disclosures of noncash investing and financing activities
Accrued property and equipment	247	128
Leasehold improvements paid by landlord	1,268	121
Public offering costs unpaid at year end	$ 420
Accretion of Series A-1, A-2, B, C, D and E redeemable convertible preferred stock to redemption value		4,570	$ 6,908
Conversion of redeemable and convertible preferred stock to common stock		117,383
Conversion of preferred warrants to common stock		$ 1,226

Nature of Business

Nature of Business	12 Months Ended
	Dec. 31, 2015
Nature of Business
Nature of Business	1. Nature of Business T2 Biosystems, Inc. (the “Company”) was incorporated on April 27, 2006 as a Delaware corporation with operations based in Lexington, Massachusetts. The Company is an in vitro diagnostic company that has developed an innovative and proprietary platform that enables rapid, sensitive and simple direct detection of pathogens, biomarkers and other abnormalities across a variety of unpurified patient sample types. The Company is using its T2 Magnetic Resonance platform (“T2MR”) to develop a broad set of applications aimed at reducing mortality rates, improving patient outcomes and reducing the cost of healthcare by helping medical professionals make targeted treatment decisions earlier. The Company’s initial development efforts target sepsis, hemostasis and Lyme disease, areas of significant unmet medical need in which existing therapies could be more effective with improved diagnostics. On September 22, 2014, the Company received market authorization from the U.S. Food and Drug Administration (“FDA”) for its first two products, the T2Dx Instrument (“T2Dx”) and T2Candida Panel (“T2Candida”). The Company has devoted substantially all of its efforts to research and development, business planning, recruiting management and technical staff, acquiring operating assets, raising capital, and, most recently, the commercialization of its products. Liquidity At December 31, 2015 , the Company had cash and cash equivalents of $73.7 million and an accumulated deficit of $148.9 million. The future success of the Company is dependent on its ability to successfully commercialize its FDA approved products, obtain regulatory clearance for and successfully launch its future product candidates and ultimately attain profitable operations, and obtain additional capital. Historically, the Company has funded its operations primarily through its August 2014 initial public offering, its December 2015 secondary public offering, private placements of redeemable convertible preferred stock and through debt financing arrangements. Management believes that its existing cash and cash equivalents at December 31, 2015 , together with the additional remaining liquidity of up to $10.0 million available under an Equipment Lease Facility (the “Facility”) entered into in October 2015 to help the Company meet its capital equipment needs, will be sufficient to allow the Company to fund its current operating plan through at least the next 12 months. The Company is subject to a number of risks similar to other newly commercial life science companies, including, but not limited to commercially launching the Company’s products, development and market acceptance of the Company’s product candidates, development by its competitors of new technological innovations, protection of proprietary technology, and raising additional capital.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2015
Summary of Significant Accounting Policies
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation and Consolidation The Company’s financial statements have been prepared in conformity with generally accepted accounting principles in the United States of America (“GAAP”). Any reference in these notes to applicable guidance is meant to refer to the authoritative United States generally accepted accounting principles as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Updates (“ASU”) of the Financial Accounting Standards Board (“FASB”). The Company’s consolidated financial statements include the accounts of the Company and its wholly-owned subsidiary, T2 Biosystems Securities Corporation. All intercompany balances and transactions have been eliminated. Use of Estimates The preparation of the Company’s consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. The Company utilizes certain estimates in the determination of the fair value of its stock options, deferred tax valuation allowances, revenue recognition, to record expenses relating to research and development contracts and to classify the value of instrument raw material and work-in-process inventory between inventory and property and equipment. The Company bases its estimates on historical experience and other market ‑specific or other relevant assumptions that it believes to be reasonable under the circumstances. Actual results could differ from such estimates. Segment Information Operating segments are defined as components of an enterprise about which separate discrete information is available for evaluation by the chief operating decision maker, or decision ‑making group, in deciding how to allocate resources and in assessing performance. The Company’s chief operating decision maker is the Chief Executive Officer. The Company views its operations and manages its business in one operating segment, which is the business of developing and, upon regulatory clearance, launching commercially its diagnostic products aimed at reducing mortality rates, improving patient outcomes and reducing the cost of healthcare by helping medical professionals make targeted treatment decisions earlier. Off ‑Balance Sheet Risk and Concentrations of Credit Risk The Company has no significant off-balance sheet risks, such as foreign exchange contracts, option contracts, or other foreign hedging arrangements. Cash and cash equivalents are financial instruments that potentially subject the Company to concentrations of credit risk. At December 31, 2015 and 2014, substantially all of the Company’s cash was deposited in accounts at one financial institution, with a significant amount invested in money market funds that are invested in short-term U.S. government agency securities. The Company maintains its cash deposits, which at times may exceed the federally insured limits, with a large financial institution and, accordingly, the Company believes such funds are subject to minimal credit risk. For the year end December 31, 2015, the Company derived approximately 50% of its total revenue from one customer and 25% of its total revenue from a second customer. For the year ended December 31, 2014, the Company derived all of its revenue from a single customer. Cash Equivalents Cash equivalents include all highly liquid investments maturing within 90 days from the date of purchase. Cash equivalents consist of money market funds invested in short-term U.S. government agency securities as of December 31, 2015 and 2014. Accounts Receivable The Company’s accounts receivable consists of amounts due from commercial customer s and from research and development arrangements with partners. At each reporting period, management reviews all outstanding balances to determine if the facts and circumstances of each customer relationship indicate the need for a reserve. The Company does not require collateral and did not have an allowance for accounts at December 31, 2015 or 2014. Inventories Inventories are stated at the lower of cost or market. The Company determines the cost of its inventories, which includes amounts related to materials, direct labor, and manufacturing overhead, on a first-in, first-out basis. The Company performs an assessment of the recoverability of capitalized inventory during each reporting period, and writes down any excess and obsolete inventories to their realizable value in the period in which the impairment is first identified. Shipping and handling costs incurred for inventory purchases are capitalized and recorded upon sale in cost of product revenues in the consolidated statements of operations and comprehensive loss or are included in the value of T2-owned instruments and components, a component of property and equipment, net, and depreciated. The Company capitalizes inventories in preparation for sales of products when the related product candidates are considered to have a high likelihood of regulatory clearance, which for the T2Dx Instrument and T2Candida Panel was upon the achievement of regulatory clearance, and the related costs are expected to be recoverable through sales of the inventories. In addition, the Company capitalizes inventories related to the manufacture of instruments that have a high likelihood of regulatory clearance, which for the T2Dx Instrument was upon the achievement of regulatory clearance, and will be retained as the Company’s assets, upon determination that the instrument has alternative future uses. In determining whether or not to capitalize such inventories, the Company evaluates, among other factors, information regarding the product candidate’s status of regulatory submissions and communications with regulatory authorities, the outlook for commercial sales and alternative future uses of the product candidate. Costs associated with development products prior to satisfying the inventory capitalization criteria are charged to research and development expense as incurred. The Company classifies inventories related to instruments that are Company-owned, as a component of property and equipment. Raw material and work-in-process inventories that are expected to be used to produce Company-owned instruments, based on our business model and forecast, are also classified as property and equipment. Company-owned instruments are instruments that are manufactured and placed with customers in connection with reagent rental agreements, or are used for internal purposes. The components of inventory consist of the following (in thousands): December 31, December 31, 2015 2014 Raw materials $ $ Work-in-process Finished goods — Total inventories $ $ Fair Value Measurements The Company is required to disclose information on all assets and liabilities reported at fair value that enables an assessment of the inputs used in determining the reported fair values. ASC 820, Fair Value Measurements and Disclosures (“ASC 820”), establishes a hierarchy of inputs used in measuring fair value that maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that the observable inputs be used when available. Observable inputs are inputs that market participants would use in pricing the asset or liability based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company’s assumptions about the inputs that market participants would use in pricing the asset or liability, and are developed based on the best information available in the circumstances. The fair value hierarchy applies only to the valuation inputs used in determining the reported fair value of the investments and is not a measure of the investment credit quality. The hierarchy defines three levels of valuation inputs: Level 1 — Quoted unadjusted prices for identical instruments in active markets. Level 2 — Quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, and model ‑derived valuations in which all observable inputs and significant value drivers are observable in active markets. Level 3 — Model derived valuations in which one or more significant inputs or significant value drivers are unobservable, including assumptions developed by the Company. The fair value hierarchy prioritizes valuation inputs based on the observable nature of those inputs. Assets and liabilities measured at fair value are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires management to make judgments and consider factors specific to the asset or liability (See Note 3). Financial instruments measured at fair value on a recurring basis include cash, money market funds and restricted cash (See Note 3). For certain financial instruments, including accounts payable and accrued expenses, the carrying amounts approximate their fair values as of December 31, 2015 and 2014 because of their short-term nature. At December 31, 2015 and 2014, the carrying value of the Company’s debt approximated fair value, which was determined using Level 3 inputs, including a quoted interest rate (Note 6). Property and Equipment Property and equipment are recorded at cost and depreciated over their estimated useful lives using the straight ‑line method. Property and equipment includes raw materials, work-in-process and finished instruments that are Company-owned or expected to remain Company-owned when placed in service. Company-owned instruments are instruments that are manufactured and placed with customers in connection with reagent rental agreements, or are used for internal purposes. Repairs and maintenance costs are expensed as incurred, whereas major improvements are capitalized as additions to property and equipment. Revenue Recognition The Company generates revenue from product sales, which includes the sale of T2Dx, consumable diagnostic tests and related services, and research and development agreements with third parties. The Company recognizes revenue in accordance with FASB ASC Topic 605, Revenue Recognition (“ASC 605”). Accordingly, the Company recognizes revenue when all of the following criteria have been met: i. Persuasive evidence of an arrangement exists ii. Delivery has occurred or services have been rendered iii. The seller’s price to the buyer is fixed or determinable iv. Collectability is reasonably assured If any of the above criteria have not been met, the Company defers revenue until such time each of the criteria have been satisfied. Product revenue is generated by the sale of T2Dx and consuma ble diagnostic tests. The Company either sells T2Dx to customers, or retains title and places a T2Dx at the customer site pursuant to a reagent rental agreement. When a T2Dx is directly purchased by a customer, the Company recognizes revenue when all applicable revenue recognition criteria are met. When a T2Dx is placed under a reagent rental agreement, the Company’s customers generally agree to long-term agreements, certain of which may include minimum purchase commitments and/or incremental charge s on each consumable diagnostic test purchased, which varies based on the monthly volume of test cartridges purchased. Revenue from the sale of consumable diagnostic tests, which includes the incremental charge, is recognized upon delivery as a component of product revenue in the Company’s consolidated statements of operations and comprehensive loss. Direct sales of T2Dx include warranty, maintenance and technical support services for one year following the installation of the purchased T2Dx (“Maintenance Se rvices”). After the completion of the initial Maintenance Services period, customers have the option to renew the Maintenance Services for additional one year periods in exchange for additional consideration. In addition, the Company may provide training to customers. The Company defers revenue from the initial sale of T2Dx equal to the relative fair value of the one year of Maintenance Services and training and recognizes the amounts ratably over the service delivery period. The Company warrants that consumable diagnostic tests will be free from defects, when handled according to product specifications, for the stated life of the product. To fulfill valid warranty claims, the Company provides a credit to its customers on future orders. Accordingly, the Company defers revenue associated with the estimated defect rates of the consumable diagnostic tests. The Company does not offer rights of return for T2Dx or consumable diagnostic tests. Shipping and handling costs incurred associated with products sold to customers are recorded as a cost of product revenue in the consolidated statement of operations and comprehensive loss. Shipping and handling costs billed to customers in connection with a product sale are recorded as a component of product revenue in the consolidated statements of operations and comprehensive loss. For multiple-element arrangements, the Company identifies the deliverables included within each agreement and evaluates which deliverables represent separate units of accounting. The determination that multiple elements in an arrangement meet the criteria for separate units of accounting requires the Company’s management to exercise judgment. The Company accounts for those components as separate elements when the following criteria are met: (1) the delivered items have value to the customer on a stand-alone basis; and, (2) if there is a general right of return relative to the delivered items, delivery or performance of the undelivered items is considered probable and within its control. The consideration received is allocated among the separate units of accounting based on a selling price hierarchy. The selling price hierarchy is based on: (1) vendor specific objective evidence (“VSOE”), if available; (2) third party evidence of selling price if VSOE is not available; or (3) best estimated selling price (“BESP”) if neither VSOE nor third party evidence is available. The Company generally expects that it will not be able to establish selling price using third-party evidence due to the nature of our products and the markets in which the Company compete s , and, as such, the Company typically will determine selling price using VSOE or BESP. When the Company establishes selling price using BESP, consideration is given to both market and Company-specific factors, including the cost to produce the deliverable and the anticipated margin on that deliverable, as well as the characteristics of markets in which the deliverable is sold. Revenue earned from activities performed pursuant to research and development agreements is reported as research revenue in the consolidated statements of operations and comprehensive loss, using the proportional performance method as the work is completed, limited to payments earned, and the related costs are expensed as incurred as research and development expense. The timing of receipt of cash from the Company’s research and development agreements generally differs from when revenue is recognized. Cost of Product Revenue Cost of product revenue includes the cost of materials, direct labor and manufacturing overhead costs used in the manufacture of consumable diagnostic tests sold to customers and related license and royalty fees. Cost of product revenue also includes depreciation on revenue generating T2Dx that have been placed with customers under reagent rental agreements; costs of materials, direct labor and manufacturing overhead costs on T2Dx sold to customers; and other costs such as customer support costs, royalties and license fees, warranty and repair and maintenance expense on T2Dx that have been placed with customers under reagent rental agreements. Research and Development Costs Costs incurred in the research and development of the Company’s product candidates are expensed as incurred. Research and development expenses consist of costs incurred in performing research and development activities, including activities associated with performing services under research revenue arrangements, and include salaries and benefits, stock compensation, research ‑related facility and overhead costs, laboratory supplies, equipment and contract services. Impairment of Long Lived Assets The Company reviews long ‑lived assets, including capitalized T2 owned equipment and components , for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. During this review, the Company reevaluates the significant assumptions used in determining the original cost and estimated lives of long ‑lived assets. Although the assumptions may vary from asset to asset, they generally include operating results, changes in the use of the asset, cash flows and other indicators of value. Management then determines whether the remaining useful life continues to be appropriate or whether there has been an impairment of long ‑lived assets based primarily upon whether expected future undiscounted cash flows are sufficient to support the assets’ recovery. If impairment exists, the Company would adjust the carrying value of the asset to fair value, generally determined by a discounted cash flow analysis. No impairment charges have been recorded in any of the periods presented. Comprehensive Loss Comprehensive loss is defined as the change in equity of a business enterprise during a period from transactions and other events and circumstances from non ‑owner sources. Comprehensive loss consists of net loss and other comprehensive loss, which includes certain changes in equity that are excluded from net loss. The Company’s comprehensive loss equals reported net loss for all periods presented. Stock Based Compensation The Company has a stock ‑based compensation plan which is more fully described in Note 9. The Company records stock ‑based compensation for options granted to employees and to members of the board of directors for their services on the board of directors, based on the grant date fair value of awards issued, and the expense is recorded on a straight ‑line basis over the applicable service period, which is generally four years. The Company accounts for non ‑employee stock ‑based compensation arrangements based upon the fair value of the consideration received or the equity instruments issued, whichever is more reliably measurable. The measurement date for non ‑employee awards is generally the date that the performance of services required for the non ‑employee award is complete. Stock ‑based compensation costs for non ‑employee awards is recognized as services are provided, which is generally the vesting period, on a straight ‑line basis. The Company expenses restricted stock awards based on the fair value of the award on the date of issuance, on a straight ‑line basis over the associated service period of the award. The Company uses the Black ‑Scholes ‑Merton option pricing model to determine the fair value of stock options. The use of the Black ‑Scholes ‑Merton option ‑pricing model requires management to make assumptions with respect to the expected term of the option, the expected volatility of the common stock consistent with the expected life of the option, risk ‑free interest rates and expected dividend yields of the common stock. The expected term was determined according to the simplified method, which is the average of the vesting tranche dates and the contractual term. Due to the lack of a public market for the trading of the Company’s common stock and a limited amount of company ‑specific historical and implied volatility data, the Company base s its estimate of expected volatility primarily on the historical volatility of a group of similar companies that are publicly traded. For these analyses, companies with comparable characteristics a re selected, including enterprise value and position within the industry, and with historical share price information sufficient to meet the expected life of the stock ‑based awards. The Company compute s the historical volatility data using the daily closing prices for the selected companies’ shares during the equivalent period of the calculated expected term of its stock ‑based awards. The risk ‑free interest rate is determined by reference to U.S. Treasury zero ‑coupon issues with remaining maturities similar to the expected term of the options. The Company has not paid, and does not anticipate paying, cash dividends on shares of common stock; therefore, the expected dividend yield is assumed to be zero . The Company is required to estimate forfeitures at the time of grant and revise those estimates in subsequent periods if actual forfeitures differ from those estimates. Income Taxes The Company provides for income taxes using the liability method. The Company provides deferred tax assets and liabilities for the expected future tax consequences of temporary differences between the Company’s financial statement carrying amounts and the tax basis of assets and liabilities using enacted tax rates expected to be in effect in the years in which the differences are expected to reverse. A valuation allowance is provided to reduce the deferred tax assets to the amount that will more likely than not be realized. The Company applies ASC 740 Income Taxes (“ASC 740”) in accounting for uncertainty in income taxes. The Company does not have any material uncertain tax positions for which reserves would be required. The Company will recognize interest and penalties related to uncertain tax positions, if any, in income tax expense. Guarantees As permitted under Delaware law, the Company indemnifies its officers and directors for certain events or occurrences while the officer or director is, or was, serving at the Company’s request in such capacity. The term of the indemnification is for the officer’s or director’s lifetime. The maximum potential amount of future payments the Company could be required to make is unlimited; however, the Company has directors’ and officers’ insurance coverage that limits its exposure and enables it to recover a portion of any future amounts paid. The Company leases office, laboratory and manufacturing space under noncancelable operating leases. The Company has standard indemnification arrangements under the leases that require it to indemnify the landlord against all costs, expenses, fines, suits, claims, demands, liabilities, and actions directly resulting from any breach, violation or nonperformance of any covenant or condition of the Company’s leases. As of December 31, 2015 and 2014, the Company had not experienced any material losses related to these indemnification obligations, and no material claims with respect thereto were outstanding. The Company does not expect significant claims related to these indemnification obligations and, consequently, concluded that the fair value of these obligations is negligible, and no related reserves were established. Net Loss Per Share Basic net loss per share is calculated by dividing net loss applicable to common stockholders by the weighted ‑average number of shares outstanding during the period, without consideration for common stock equivalents. Diluted net loss per share is calculated by adjusting the weighted ‑average number of shares outstanding for the dilutive effect of common stock equivalents outstanding for the period, determined using the treasury ‑stock method. For purposes of the diluted net loss per share calculation, redeemable convertible preferred stock, and warrants to purchase redeemable convertible preferred stock, which were outstanding prior to the Company’s IPO, and stock options and unvested restricted stock are considered to be common stock equivalents, but have been excluded from the calculation of diluted net loss per share, as their effect, including the related impact to the numerator of the fair value adjustment of the warrants and the impact to the denominator of the warrant shares, would be anti ‑dilutive for all periods presented. Therefore, basic and diluted net loss per share applicable to common stockholders were the same for all periods presented. Recently Issued Accounting Pronouncements From time to time, new accounting pronouncements are issued by the FASB or other standard setting bodies and adopted by the Company as of the specified effective date. Unless otherwise discussed, the Company believes that the impact of recently issued standards that are not yet effective will not have a material impact on its financial position or results of operations upon adoption. In February 2016, the FASB issued ASU No. 2016-02, Leases (“ASU 2016-02”), which applies to all leases and will require lessees to put most leases on the balance sheet, but recognize expense in a manner similar to the current standard. ASU 2016-02 is effective for fiscal years beginning after December 15, 2018 and interim periods within those years, which is the year ended December 31, 2019 for the Company. Entities are required to use a modified retrospective approach of adoption for leases that exist or are entered into after the beginning of the earliest comparative period in the financial statements. Full restrospective application is prohibited. The Company is evaluating the new guidance and the expected effect on the Company’s consolidated financial statements. In November 2015, the FASB issued ASU No. 2015-17, Balance Sheet Classification of Deferred Taxes (“ASU 2015-17”). The standard requires all companies to report deferred tax assets and liabilities as noncurrent, which modifies the current standard, which requires deferred tax assets and liabilities to be classified as current or noncurrent based on how the related assets or liabilities are classified. ASU 2015-17 is effective for fiscal years beginning after December 15, 2015, and for interim periods within those annual periods. Early adoption is permitted and may be applied prospectively or retrospectively. The Company has adopted ASU 2015-17 as of December 31, 2015 on a prospective basis, which resulted the netting of deferred tax assets and liabilities on the consolidated balance sheet. In July 2015, the FASB issued ASU No. 2015-11, Inventory (Topic 330): Simplifying the Measurement of Inventory (“ASU 2015-11”). The standard simplifies the subsequent measurement of inventory by requiring inventory to be measured at the lower of cost and net realizable value for entities using the first-in-first out method of valuing inventory. ASU 2015-11 eliminates other measures required by current guidance to determine net realizable value. ASU 2015-11 is effective for fiscal years beginning after December 15, 2016 and interim periods within those fiscal years and early adoption is permitted. The Company has not adopted ASU 2015-11 and does not expect the new guidance to have a material effect on its consolidated financial statements. In April 2015, the FASB issued ASU No. 2015-05, Customer’s Accounting for Fees Paid in a Cloud Computing Arrangement (“ASU 2015-05”). The standard clarifies that customers in cloud computing arrangements should determine whether the arrangement includes a license of software by applying the same guidance as cloud service providers and eliminates the existing requirement for customers to account for software licenses acquired by analogizing to the guidance on leases. It is effective for annual periods beginning on or after December 15, 2015, including interim periods within those annual periods, and early adoption is permitted. Adoption of ASU 2015-05 can either be applied (1) prospectively to all arrangements entered into or materially modified after the effective date or (2) retrospectively. The Company has not adopted the guidance prescribed by ASU 2015-05 and does not expect the new guidance to have a material effect on its consolidated financial statements. In April 2015, the FASB issued ASU No. 2015-03, Simplifying the Presentation of Debt Issuance Costs (“ASU 2015-03”). This standard amends existing guidance to require the presentation of debt issuance costs in the balance sheet as a deduction from the carrying amount of the related debt liability instead of a deferred charge. It is effective for annual reporting periods beginning after December 15, 2015, but early adoption is permitted. Adoption of ASU 2015-03 is applied retrospectively. The Company has not adopted the guidance prescribed by ASU 2015-03. However, had the Company adopted this guidance as of December 31, 2015, the Company would reclassify a total of $151,000 of deferred financing costs from other current assets and other assets on the consolidated balance sheet and reduce the total notes payable balance accordingly. In June 2014, the FASB issued amended guidance, ASU No. 2014-09, Revenue from Contracts with Customers (“ASU 2014-09”), which is applicable to revenue recognition that will now be effective for the Company for the year ending December 31, 2018, as a result of the deferral of the effective date adopted by the FASB in July 2015. The new guidance must be adopted using either a full retrospective approach for all periods presented or a modified retrospective approach. Early adoption prior to the original adoption date of ASU 2014-09 is not permitted. The new guidance applies a more principles-based approach to revenue recognition. The Company is evaluating the new guidance and the expected effect on the Company’s consolidated financial statements. In 2014, the FASB issued ASU 2014-15, Presentation of Financial Statements – Going Concern (“ASU 2014-15”), which is effective for annual periods ending after December 15, 2016. Early adoption is permitted. ASU 2014-15 provides new guidance on (1) management’s responsibility in evaluating whether or not there is substantial doubt about a company’s ability to continue as a going concern within one year from the date the financial statements are issued each reporting period and (2) related financial statement disclosures. The Company has not adopted the guidance prescribed by ASU 2014-15. However, had the Company applied the guidance prescribed by ASU 2014-15 as of December 31, 2015, the Company would determine that there is not substantial doubt about its ability to continue as a going concern for at least one year from date the financial statements are issued .

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2015
Fair Value Measurements
Fair Value Measurements	3. Fair Value Measurements The Company measures the following financial assets at fair value on a recurring basis. There were no transfers between levels of the fair value hierarchy during any of the periods presented. The following tables set forth the Company’s financial assets and liabilities carried at fair value categorized using the lowest level of input applicable to each financial instrument as of December 31, 2015 and 2014 (in thousands): Quoted Prices in Active Significant Markets for Other Significant Balance at Identical Observable Unobservable December 31, Assets Inputs Inputs 2015 (Level 1) (Level 2) (Level 3) Assets: Cash $ $ $ — $ — Money market funds — — Restricted cash — — $ $ $ — $ — Quoted Prices in Active Significant Markets for Other Significant Balance at Identical Observable Unobservable December 31, Assets Inputs Inputs 2014 (Level 1) (Level 2) (Level 3) Assets: Cash $ $ $ — $ — Money market funds — — Restricted cash — — $ $ $ — $ —

Restricted cash

Restricted cash	12 Months Ended
	Dec. 31, 2015
Restricted Cash
Restricted cash	4. Restricted Cash The Company is required to maintain a security deposit for its operating lease agreement for the duration of the lease agreement and for its credit cards as long as they are in place. At both December 31, 2015 and 2014, the Company had certificates of deposit for $260,000 and $340,000 , respectively, which represented collateral as security deposits for its operating lease agreement for its facility and its credit card. In accordance with the operating lease agreement, the Company reduced its security deposit by $80,000 to $240,000 in June 2015.

Supplemental Balance Sheet Info

Supplemental Balance Sheet Information	12 Months Ended
	Dec. 31, 2015
Supplemental Balance Sheet Information
Supplemental Balance Sheet Information	5. Supplemental Balance Sheet Information Property and Equipment Property and equipment consists of the following (in thousands) Estimated Useful December 31, Life (Years) 2015 2014 Office and computer equipment 3 $ $ Software 3 Laboratory equipment 5 Furniture 5 - 7 Manufacturing equipment 5 — Manufacturing tooling and molds 0.5 T2 instruments and components 5 Leasehold improvements Lesser of useful life or lease term Construction in progress n/a Less accumulated depreciation and amortization Property and equipment, net $ $ Construction in progress is primarily comprised of equipment and leasehold improvement construction projects that ha ve not been placed in service. T2 instruments and components is comprised of raw materials and work-in-process inventory that are expected to be used or used to produce Company-owned instruments, based on our business model and forecast, and completed instruments that will be used for internal research and development or reagent rental agreements with customers. Completed T2 instruments are placed in service once installation procedures are completed and are depreciated over five years. The Company has approximatel y $1.9 millio n of Company-owned T2 instruments installed and depreciating as of December 31, 2015. Depreciation expense for Company-owned T2 instruments placed at customer sites pursuant to reagent rental agreements is recorded as a component of cost of product revenue and totaled approximately $105,000 for the year ended December 31, 2015. Depreciation expense for T2 instruments used for internal research and development is recorded as a component of research and development expense. Depreciation and amortization expense of $1.5 million, $691,000 and $584,000 was charged to operations for the years ended December 31, 2015, 2014 and 2013, respectively. Accrued Expenses Accrued expenses consist of the following (in thousands): December 31, 2015 2014 Accrued payroll and compensation $ $ Accrued research and development expenses Accrued professional services Other accrued expenses Total accrued expenses $ $

Debt

Debt	12 Months Ended
	Dec. 31, 2015
Debt
Debt	6. Debt On July 11, 2014, the Company entered into a loan and security agreement (“Note Agreement 1”) with two lenders to borrow up to $30.0 million for operations. Note Agreement 1 allows the Company to borrow amounts in two tranches, up to $20.0 million (drawn in amounts not less than $10.0 million upon closing and the remainder drawn in amounts not less than $5.0 million draws) for tranche A and up to $10.0 million for tranche B. The Company borrowed the full $20.0 million available under tranche A by December 31, 2014. In May 2015, the Company entered into the First Amendment to Note Agreement 1 whereby the availability to draw up to $10.0 million for tranche B was extended from June 30, 2015 to December 31, 2015. Commencing July 1, 2015, the Company incurred a fee equal to 1.0% per annum of any undrawn amounts under tranche B. This fee is payable on the date tranche B is drawn or upon the expiration of the draw period. The Company paid the $50,000 fee upon drawing the remaining $10.0 million under tranche B on December 28, 2015. All other terms of Note Agreement 1 remain in effect. In October 2015, the Company entered into the Second Amendment to Note Agreement 1 to enable the Company to enter into the Equipment Lease Facility (Note 13). Through December 31, 2015, the Company received proceeds of $29.7 million under tranches A and B, net of issuance costs. The amounts borrowed under Note Agreement 1 are collateralized by substantially all of the assets of the Company and bear interest at the one-month LIBOR plus 7.05% , which was 7.28% on December 31, 2015. The Company will pay interest only payments on the amounts borrowed under Note Agreement 1 through July 31, 2016. After the interest only period, the Company will repay the amounts borrowed in equal monthly installments until the maturity date of July 1, 2019. Note Agreement 1 requires payment of a final fee of 4.75% of the aggregate original principal of amounts borrowed, which the Company is accruing over the term of Note Agreement 1. In addition, amounts borrowed may be prepaid at the option of the Company in denominations of not less than $1.0 million, and any amounts prepaid are subject to a prepayment premium of 1.0% if prepaid prior to the second anniversary of the borrowing date and 0.5% if prepaid prior to the maturity date and after the second anniversary of the borrowing date. The effective interest rate for Note Agreement 1, including final fee interest and non-cash interest, is 9.7% . Note Agreement 1 does not include any financial covenants, but does contain a subjective acceleration clause whereby upon an event of default, which includes a material adverse change in the business, operations, or conditions (financial or otherwise) of the Company or a material impairment of the prospect of repayment of any portion of the obligations, the lender may accelerate the Company’s repayment obligations under Note Agreement 1. In the event of default, the lender has first priority to substantially all of the Company’s assets. The lender has not exercised its right under this clause, as there have been no such events. The Company believes the likelihood of the lender exercising this right is remote. The Company assessed all terms and features of Note Agreement 1 in order to identify any potential embedded features that would require bifurcation or any beneficial conversion features. As part of this analysis, the Company assessed the economic characteristics and risks of Note Agreement 1, including put and call features. The Company determined that all features of Note Agreement 1 are clearly and closely associated with a debt host and do not require bifurcation as a derivative liability, or the fair value of the feature is immaterial. The Company will continue to reassess the features to determine if they require separate accounting on a quarterly basis. On June 25, 2012, the Company entered into a loan and security agreement (“Note Agreement 2”) with a lender to borrow up to $4.5 million for operations through December 31, 2012. The amounts borrowed are collateralized by the assets of the Company and bear interest at 6.25% . The Company paid interest only on the borrowings through June 30, 2013 and then makes 36 equal month payments of principal plus monthly payments of accrued interest. During 2012, the Company borrowed $4.5 million under the agreement. The debt can be prepaid at the option of the Company, and is subject to a prepayment premium of 2% if it is repaid prior the first anniversary of the borrowing date, and 1% if the debt is prepaid prior to the second anniversary of the borrowing date. In connection with the closing of Note Agreement 1, the Company repaid all amounts outstanding under Note Agreement 2, totaling approximately $2.9 million, as of July 11, 2014. On May 9, 2011, the Company entered into a promissory agreement (“Note Agreement 3”) with a separate lender to borrow up to $1.7 million for the purchase of laboratory equipment and office equipment through December 2013. The amounts borrowed are collateralized by the associated equipment and bear interest at 6.5% . The Company paid interest only on the borrowings through December 2013 and will make equal monthly payments of principal and interest through the maturity date of May 2018. The Company borrowed a total of $1.4 million under Note Agreement 3. Note Agreement 3 includes financial covenants that require the Company to maintain a minimum cash balance of $300,000 . In addition, Note Agreement 3 contains a subjective acceleration clause whereby an event of default and immediate acceleration of the borrowing under the security and loan agreement occurs if there is a material adverse change in the business, operations, or condition (financial or otherwise) of the Company or a material impairment of the prospect of repayment of any portion of the obligations. In the event of default, the lender has first priority on the laboratory equipment and office equipment purchased with the proceeds from Note Agreement 3. The lender has not exercised its right under this clause, as there have been no such events. The Company believes that the likelihood of the lender exercising this right is remote. Interest expense for the years ended December 31, 2015, 2014 and 2013 was $2.0 million, $741,000 , and $410,000 , respectively. Interest expense for the years ended December 31, 2015, 2014, and 2013 included non-cash interest of $354,000 , $ 112,000, and $44,000 , respectively, related to the amortization of debt discounts and deferred financing costs under each of the Note Agreements. Future principal payments on the notes payable as of December 31, 2015 are as follows (in thousands): Year ended December 31, 2016 $ 2017 2018 2019 Total debt payments Less current portion (principal) Less debt discount Notes payable, net of current portion $

Redeemable Convertible Preferre

Redeemable Convertible Preferred Stock	12 Months Ended
	Dec. 31, 2015
Redeemable Convertible Preferred Stock.
Redeemable Convertible Preferred Stock	7. Redeemable Convertible Preferred Stock Upon closing of the IPO on August 12, 2014, all of the outstanding shares of the Company’s redeemable convertible preferred stock were converted into 12,516,298 shares of its common stock. As the p referred s tock was redeemable, the Company accreted the shares to the redemption values over the period from issuance to the redemption date. The accretion amounts are recorded as an increase to the carrying value of the p referred s tock with a corresponding charge to additional paid in capital or accumulated deficit. On the conversion date, the redeemable convertible preferred stock had a balance of $117.4 million, which was recorded in temporary equity. Upon conversion into common stock, this balance was reclassified as stockholders’ equity (deficit), reducing accumulated deficit by $21.0 million, with the residual amount of $96.3 million recorded as common stock (par value) and additional paid-in capital. The amount recorded as a reduction in accumulated deficit reflects the value of redeemable convertible preferred stock dividends and issuance costs accreted through the conversion date. As of August 12, 2014, the Company does not have any redeemable convertible preferred stock issued or outstanding. Prior to the IPO, the holders of the Company’s redeemable convertible preferred stock had certain voting, dividend, and redemption rights, as well as liquidation preferences and conversion privileges. All rights, preferences, and privileges associated with the redeemable convertible preferred stock were terminated at the time of the Company’s IPO in conjunction with the conversion of all outstanding shares of redeemable convertible preferred stock into shares of common stock.

Stockholders' Equity (Deficit)

Stockholders' Equity (Deficit)	12 Months Ended
	Dec. 31, 2015
Stockholders' Equity
Stockholders' Equity (Deficit)	8. Stockholders’ Equity (Deficit) Common Stock Each share of common stock is entitled to one vote. The holders of common stock are also entitled to receive dividends whenever funds are legally available and when declared by the board of directors, subject to the prior rights of holders of all classes of stock outstanding. As of December 31, 2015, a total of 3,484,298 shares and 552,024 shares of common stock were reserved for issuance upon (i) the exercise of outstanding stock options and (ii) the issuance of stock awards under the Company’s 2014 Incentive Award Plan and 2014 Employee Stock Purchase Plan, respectively.

Stock Based Compensation

Stock Based Compensation	12 Months Ended
	Dec. 31, 2015
Stock Based Compensation
Stock-Based Compensation	9. Stock Based Compensation Stock Incentive Plans 2006 Stock Incentive Plan The Company’s 2006 Stock Option Plan (“the 2006 Plan”) was established for granting stock incentive awards to directors, officers, employees and consultants to the Company. Upon closing of the Company’s IPO in August 2014, the Company ceased granting stock incentive awards under the 2006 Plan. The 2006 Plan provided for the grant of incentive and non-qualified stock options and restricted stock grants as determined by the Board of Directors. Under the 2006 Plan, stock options were generally granted with exercise prices equal to or greater than the fair value of the common stock as determined by the board of directors, expired no later than 10 years from the date of grant, and vest over various periods not exceeding 4 years. 2014 Stock Incentive Plan The Company’s 2014 Plan provides for the issuance of shares of common stock in the form of stock options, awards of restricted stock, awards of restricted stock unit awards, performance awards, dividend equivalent awards, stock payment awards and stock appreciation rights to directors, officers, employees and consultants of the Company. Since the establishment of the 2014 Plan, the Company has only granted stock options. Generally, stock options are granted with exercise prices equal to or greater than the fair value of the common stock on the date of grant, expire no later than 10 years from the date of grant, and vest over various periods not exceeding 4 years. The number of shares reserved for future issuance under the 2014 Plan is the sum of (1) 823,529 , (2) any shares that were granted under the 2006 Plan which are forfeited, lapse unexercised or are settled in cash subsequent to the effective date of the 2014 Plan and (3) an annual increase on the first day of each calendar year beginning January 1, 2015 and ending on January 1, 2024, equal to the lesser of (A) 823,529 shares, (B) 4% of the shares outstanding on the final day of the immediately preceding calendar year and (C) such smaller number of shares determined by the Board of Directors. As of December 31, 2015 there were 395,133 shares available for future grant under the Plan. Stock Options During the years ended December 31, 2015, 2014, and 2013, the Company granted options with an aggregate fair value of $10.1 million and $6.0 million, and $2.0 million, respectively, which are being amortized into compensation expense over the vesting period of the options as the services are being provided. The following is a summary of option activity under the Plan (in thousands, except share and per share amounts): Weighted-Average Weighted-Average Remaining Number of Exercise Price Per Contractual Term Aggregate Intrinsic Shares Share (In years) Value Outstanding at December 31, 2014 $ $ Granted Exercised Cancelled Outstanding at December 31, 2015 Exercisable at December 31, 2015 Vested or expected to vest at December 31, 2015 The weighted ‑average fair values of options granted in the years ended December 31, 2015, 2014, and 2013 were $8.42 , $7.59 , and $1.85 per share, respectively, and were calculated using the following estimated assumptions: Year ended December 31, 2015 2014 2013 Weighted-average risk-free interest rate % % % Expected dividend yield % % % Expected volatility % % % Expected terms years years years The total fair values of stock options that vested during the years ended December 31, 2015, 2014, and 2013 were $ 4.0 million, $ 1.2 million, and $476,000 , respectively. Employee Stock Purchase Plan The 2014 ESPP plan period is semi-annual and allows participants to purchase the Company’s common stock at 85% of the lower of (i) the market value per share of common stock on the first day of the offering period or (ii) the market value per share of the common stock on the purchase date. Each participant can purchase up to a maximum of $25,000 per calendar year in fair market value. The first plan period began on August 7, 2014. Stock-based compensation expense from the 2014 ESPP for the years ended December 31, 2015 and 2014 was $233,000 and $103,000 , respectively. The 2014 ESPP provides initially for the granting of up to 220,588 shares of the Company’s common stock to eligible employees. In addition, on the first day of each calendar year beginning January 1, 2015 and ending on January 1, 2024, the number of common shares available under the Plan shall be increased by the number of shares equal to the lesser of (1) 220,588 shares, (2) 1% of the common shares outstanding on the final day of the immediately preceding calendar year and (3) such smaller number of common shares as determined by the Board of Directors. At December 31, 2015, there were 156,891 shares available under the 2014 ESPP. Stock ‑Based Compensation Expense The following table summarizes the stock-based compensation expense for stock options granted to employees and non-employees, as well as stock-compensation expense for the 2014 ESPP that was recorded in the Company’s results of operations for the years presented (in thousands): Year ended December 31, 2015 2014 2013 Research and development $ $ $ Selling, general and administrative Total stock-based compensation expense $ $ $ For the year ended December 31, 2015, $48,000 of stock-based compensation expense was included in cost of product revenue and $67,000 was capitalized as part of inventory or T2 instruments and components. As of December 31, 2015, there was $ 11.3 million of total unrecognized compensation cost related to non ‑vested stock options granted under the Stock Incentive Plans. Total unrecognized compensation cost will be adjusted for future changes in the estimated forfeiture rate. The Company expects to recognize that cost over a remaining weighted ‑average period of 2.91 years.

Warrants

Warrants	12 Months Ended
	Dec. 31, 2015
Warrants
Warrants	10. Warrants Prior to the completion of the IPO, the Company had outstanding warrants to purchase 250,727 shares of various classes of redeemable convertible preferred stock. The warrants were recorded as a liability and changes in the fair value of the warrants were recorded as a component of other income (expense), net. In connection with the closing of the Company’s IPO, all of the Company’s outstanding warrants to purchase convertible preferred stock automatically converted into 68,700 shares of common stock, resulting in the net settlement of the liability to purchase redeemable securities to common stock (par value) and additional paid-in capital as of August 12, 2014.

Net Loss Per Share

Net Loss Per Share	12 Months Ended
	Dec. 31, 2015
Net Loss Per Share
Net Loss Per Share	11. Net Loss Per Share The following table presents the calculation of basic and diluted net loss per share applicable to common stockholders (in thousands, except share and per share data): Year ended December 31, 2015 2014 2013 Numerator: Net loss $ $ $ Accretion of redeemable convertible preferred stock to redemption value — Net loss applicable to common stockholders $ $ $ Denominator: Weighted-average number of common shares outstanding — basic and diluted Net loss per share applicable to common stockholders — basic and diluted $ $ $ The following shares were excluded from the calculation of diluted net loss per share applicable to common stockholders, prior to the application of the treasury stock method, because their effect would have been anti ‑dilutive for the periods presented: Year ended December 31, 2015 2014 2013 Redeemable convertible preferred stock — — Options to purchase common shares Warrants to purchase redeemable convertible preferred stock — — Total

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2015
Income Taxes
Income Taxes	12. Income Taxes The reconciliation of the U.S. federal statutory rate to the Company’s effective tax rate is as follows: Year Ended December 31, 2015 2014 2013 Tax at statutory rates % % % State income taxes Permanent differences Research and development credits Change in valuation allowance Effective tax rate % % % The significant components of the Company’s deferred tax asset consist of the following at December 31, 2015 and 2014 (in thousands): December 31, 2015 2014 Deferred tax assets: Net operating loss carryforwards $ $ Tax credits Other temporary differences Start-up expenditures Stock option expenses Total deferred tax assets Deferred tax asset valuation allowance Net deferred tax assets Deferred tax liabilities: Prepaid expenses Net deferred taxes $ — $ — In 2015 and 2014, the Company did not record a benefit for income taxes related to its operating losses incurred. ASC 740 requires a valuation allowance to reduce the deferred tax assets reported if, based on the weight of available evidence, it is more likely than not that some portion or all of the deferred tax assets will not be realized. Based upon the level of historical U.S. losses and future projections over the period in which the net deferred tax assets are deductible, at this time, management believes it is more likely than not that the Company will not realize the benefits of these deductible differences , and as a result t he Company continues to maintain a valuation allowance for the full amount of the 2015 deferred tax assets. The valuation allowance increased $18.9 million, $12.7 million and $9.1 million for the years ended December 31, 2015, 2014 and 2013, respectively, primarily related to each year’s taxable loss. As of December 31, 2015, the Company had federal and state net operating losses of $126.7 million and $115.8 million, respectively, which are available to offset future taxable income, if any, through 2035. Included in the federal and state net operating losses are deductions attributable to excess tax benefits from the exercise of stock options of $2.4 million and $2.2 million, respectively. The tax benefits attributable to these deductions are credited directly to additional paid-in capital when realized. The Company also had federal and state research and development tax credits of $2.8 million and $1.5 million, respectively, which expire at various dates through 2035. Under the provisions of the Internal Revenue Code, the net operating loss and tax credit carryforwards are subject to review and possible adjustment by the Internal Revenue Service and state tax authorities. Net operating loss and tax credit carryforwards may become subject to an annual limitation in the event of certain cumulative changes in the ownership interest of significant stockholders over a three year period in excess of 50%, as defined under Sections 382 and 383 of the Internal Revenue Code, respectively, as well as similar state provisions. This could limit the amount of tax attributes that can be utilized annually to offset future taxable income or tax liabilities. The amount of the annual limitation is determined based on the value of the Company immediately prior to the ownership change. Subsequent ownership changes may further affect the limitation in future years. The Company has completed several financings since its inception which may have resulted in a change in control as defined by Sections 382 and 383 of the Internal Revenue Code, or could result in a change in control in the future. The Company has not conducted an assessment to determine whether there may have been a Section 382 or 383 ownership change. The Company has no unrecognized tax benefits. Interest and penalty charges, if any, related to uncertain tax positions would be classified as income tax expenses in the accompanying consolidated statements of operations. At December 31, 2015 and 2014, the Company had no accrued interest or penalties related to uncertain tax positions. The Company files income tax returns in the U.S. federal tax jurisdiction and various state jurisdictions. Since the Company is in a loss carryforward position, the Company is generally subject to examination by the U.S. federal, state and local income tax authorities for all tax years in which a loss carryforward is available. The Company does not have any international operations as of December 31, 2015. There are currently no federal or state audits in process.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2015
Commitments and Contingencies.
Commitments and Contingencies	13. Commitments and Contingencies Operating Leases In August 2010, the Company entered into a five -year, non-cancelable operating lease for office and laboratory space at its headquarters in Lexington, MA. The lease commenced on January 1, 2011, with the Company providing a security deposit of $400,000 . In accordance with the operating lease agreement, the Company reduced its security deposit by $80,000 to $240,000 in May 2015. In July 2014, the Company amendment the lease to expand the office and laboratory space leased. In May 2015, the Company entered into an amendment to this lease to extend the term from December 31, 2015 to December 31, 2017. In May, 2013, the Company entered into a two -year operating lease for additional office, laboratory and manufacturing space. The Company entered into an amendment in September 2015 to extend this lease term through December 31, 2017. In November, 2014 the Company entered into an agreement to rent additional office space in Lexington, MA. The term of the agreement is two years, commencing December 2014. In April 2015, the Company entered into an amendment to extend the term of this agreement. The amendment extends the agreement term from December 31, 2016 to December 31, 2017. In connection with this agreement, the Company paid a security deposit totaling $50,000 , which is recorded as a component of other assets in the consolidated balance sheets. In November, 2014, the Company entered into a lease for additional laboratory space in Lexington, MA. The lease term commenced April 1, 2015 and extends for six years. The rent expense, inclusive of the escalating rent payments, is recognized on a straight- line basis over the lease term. As an incentive to enter into the lease, the landlord paid approximately $1.4 million of the $2.2 million space build-out costs. The incentive is recorded as a component of lease incentives on the consolidated balance sheets and is amortized as a reduction in rent expense on a straight-line basis over the term of the lease. In connection with this lease agreement, the Company paid a security deposit of $281,000 , which is recorded as a component of other assets in the consolidated balance sheets. In May 2015, the Company entered into an amendment to a lease to expand existing manufacturing facilities. The lease amendment term is June 1, 2015 to December 31, 2017. Future minimum non-cancelable lease payments under the Company’s operating leases are as follows (in thousands): Year ending December 31, 2016 $ 2017 2018 2019 2020 Thereafter $ Rent expense for the years ended December 31, 2015, 2014, and 2013 was $1.6 million, $950,000 , and $628,000 , respectively. Equipment Lease Facility In October 2015, the Company signed a $10.0 million equipment lease facility to fund capital equipment needs. Under this facility, the lessor will fund capital equipment purchases presented. The Company will repay the amounts borrowed in 36 equal monthly installments from the date of the amount funded. At the end of the 36 month lease term, the Company has the option to (a) repurchase the leased equipment at the lesser of fair market value or 10% of the original equipment value, (b) extend the applicable lease for a specified period of time, which will not be less than one year, or (c) return the leased equipment to the lessor. As of December 31, 2015, the Company has not drawn any amounts under this facility. License Agreement In 2006, the Company entered into a license agreement with a third party, pursuant to which the third party granted the Company an exclusive, worldwide, sub-licenseable license under certain patent rights to make, use, import and commercialize products and processes for diagnostic, industrial and research and development purposes. The Company agreed to pay an annual license fee ranging from $5,000 to $25,000 for the royalty ‑bearing license to certain patents. For the years ended December 31, 2015 and 2014, the Company incurred $34,000 and $345,000 , respectively, for regulatory milestones, license fees and reimbursed patent costs under the agreement. The Company also issued a total of 84,678 shares of common stock pursuant to the agreement in 2006 and 2007, which were recorded at fair value at the date of issuance. Regulatory milestones totaling $300,000 became due during the year ended December 31, 2014, as the Company received FDA marketing authorization and European CE Mark for T2Dx and T2Candida. The Company is required to pay royalties on net sales of products and processes that are covered by patent rights licensed under the agreement at a percentage ranging in the low single digits, subject to reductions and offsets in certain circumstances, as well as a royalty on net sales of products that the Company sublicenses at a low double ‑digit percentage of specified gross revenue. Royalties that became due under this agreement for the year ended December 31, 2015 were immaterial.

401(k) Savings Plan

401(k) Savings Plan	12 Months Ended
	Dec. 31, 2015
401(k) Savings Plan
401(k) Savings Plan	14. 401(k) Savings Plan In March, 2008, the Company established a retirement savings plan under Section 401(k) of the Internal Revenue Code (the “401(k) Plan”). The 401(k) Plan covers substantially all employees of the Company who meet minimum age and service requirements, and allows participants to defer a portion of their annual compensation on a pretax basis. Company contributions to the 401(k) Plan may be made at the discretion of the board of directors. No contributions were made in the years ended December 31, 2015 and 2014.

Co-Development Agreement with C

Co-Development Agreement with Canon US Life Sciences	12 Months Ended
	Dec. 31, 2015
Co-Development Agreement with Canon US Life Sciences
Co-Development Agreement with Canon US Life Sciences	15. Co-Development Agreement with Canon US Life Sciences On February 3, 2015, the Company entered into a Co-Development Partnership Agreement (the “Co-Development Agreement”) with Canon U.S. Life Sciences, Inc. (“Canon US Life Sciences”) to develop a diagnostic test panel to rapidly detect Lyme disease. Under the terms of the Co-Development Agreement, the Company received an upfront payment of $2.0 million from Canon US Life Sciences and the agreement includes an additional $6.5 million of consideration upon achieving certain development and regulatory milestones for total aggregate payments of up to $8.5 million. In October 2015, the Company achieved a specified technical requirement and received $1.5 million related to the achievement of the milestone. The Company is eligible to receive an additional $5.0 million under the arrangement, in two milestone payments of $2.0 million and $3.0 million, related to the achievement of additional development and regulatory milestones. All payments under the Co-Development Agreement are non-refundable once received. The Company will retain exclusive worldwide commercialization rights of any products developed under the Co-Development Agreement, including sales, marketing and distribution and Canon US Life Sciences will not receive any commercial right and will be entitled to only receive royalty payments on the sales of all products developed under the Co-Development Agreement. Either party may terminate the Co-Development Agreement upon the occurrence of a material breach by the other party (subject to a cure period). The Company evaluated the deliverables under the Co-Development Agreement and determined that the Co-Development Agreement included one unit of accounting, the research and development services, as the joint research and development committee deliverable was deemed to be de minimus. The Company is recognizing revenue for research and development services as a component of research revenue in the consolidated financial statements as the services are delivered using the proportional performance method of accounting, limited to payments earned. Costs incurred to deliver the services under the Co-Development Agreement are recorded as research and development expense in the consolidated financial statements. The Company recorded revenue of $1.4 million for the year ended December 31, 2015 under the Co-Development Agreement , and expects to record revenue over the next two years, provided development and regulatory milestones are achieved .

Quarterly Financial Data (unaud

Quarterly Financial Data (unaudited)	12 Months Ended
	Dec. 31, 2015
Quarterly Financial Data (unaudited)
Quarterly Financial Data (unaudited)	16. Quarterly Financial Data (unaudited) Year ended December 31, 2015 (In thousands, except per share data) First Quarter Second Quarter Third Quarter Fourth Quarter Revenue: Product revenue $ $ — $ $ Research revenue Total revenue $ $ $ $ Costs and expenses: Cost of product revenue — Research and development Selling, general and administrative Total costs and expenses Loss from operations $ $ $ $ Net loss $ $ $ $ Net loss applicable to common shareholders $ $ $ $ Per share data: Net loss per common share—basic and diluted $ $ $ $ Year ended December 31, 2014 (In thousands, except per share data) First Quarter Second Quarter Third Quarter Fourth Quarter Revenue: Product revenue $ — $ — $ — $ — Research revenue — — — Total revenue $ — $ — $ — $ Costs and expenses: Cost of product revenue — — — — Research and development Selling, general and administrative Total costs and expenses Loss from operations $ $ $ $ Net loss $ $ $ $ Net loss applicable to common shareholders $ $ $ $ Per share data: Net loss per common share—basic and diluted $ $ $ $

Summary of Significant Accoun24

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2015
Summary of Significant Accounting Policies
Basis of Presentation and Consolidation	Basis of Presentation and Consolidation The Company’s financial statements have been prepared in conformity with generally accepted accounting principles in the United States of America (“GAAP”). Any reference in these notes to applicable guidance is meant to refer to the authoritative United States generally accepted accounting principles as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Updates (“ASU”) of the Financial Accounting Standards Board (“FASB”). The Company’s consolidated financial statements include the accounts of the Company and its wholly-owned subsidiary, T2 Biosystems Securities Corporation. All intercompany balances and transactions have been eliminated.
Use of Estimates	Use of Estimates The preparation of the Company’s consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. The Company utilizes certain estimates in the determination of the fair value of its stock options, deferred tax valuation allowances, revenue recognition, to record expenses relating to research and development contracts and to classify the value of instrument raw material and work-in-process inventory between inventory and property and equipment. The Company bases its estimates on historical experience and other market ‑specific or other relevant assumptions that it believes to be reasonable under the circumstances. Actual results could differ from such estimates.
Segment Information	Segment Information Operating segments are defined as components of an enterprise about which separate discrete information is available for evaluation by the chief operating decision maker, or decision ‑making group, in deciding how to allocate resources and in assessing performance. The Company’s chief operating decision maker is the Chief Executive Officer. The Company views its operations and manages its business in one operating segment, which is the business of developing and, upon regulatory clearance, launching commercially its diagnostic products aimed at reducing mortality rates, improving patient outcomes and reducing the cost of healthcare by helping medical professionals make targeted treatment decisions earlier.
Off Balance Sheet Risk and Concentrations of Credit Risk	Off ‑Balance Sheet Risk and Concentrations of Credit Risk The Company has no significant off-balance sheet risks, such as foreign exchange contracts, option contracts, or other foreign hedging arrangements. Cash and cash equivalents are financial instruments that potentially subject the Company to concentrations of credit risk. At December 31, 2015 and 2014, substantially all of the Company’s cash was deposited in accounts at one financial institution, with a significant amount invested in money market funds that are invested in short-term U.S. government agency securities. The Company maintains its cash deposits, which at times may exceed the federally insured limits, with a large financial institution and, accordingly, the Company believes such funds are subject to minimal credit risk. For the year end December 31, 2015, the Company derived approximately 50% of its total revenue from one customer and 25% of its total revenue from a second customer. For the year ended December 31, 2014, the Company derived all of its revenue from a single customer.
Cash Equivalents	Cash Equivalents Cash equivalents include all highly liquid investments maturing within 90 days from the date of purchase. Cash equivalents consist of money market funds invested in short-term U.S. government agency securities as of December 31, 2015 and 2014.
Accounts Receivable	Accounts Receivable The Company’s accounts receivable consists of amounts due from commercial customer s and from research and development arrangements with partners. At each reporting period, management reviews all outstanding balances to determine if the facts and circumstances of each customer relationship indicate the need for a reserve. The Company does not require collateral and did not have an allowance for accounts at December 31, 2015 or 2014.
Inventories	Inventories Inventories are stated at the lower of cost or market. The Company determines the cost of its inventories, which includes amounts related to materials, direct labor, and manufacturing overhead, on a first-in, first-out basis. The Company performs an assessment of the recoverability of capitalized inventory during each reporting period, and writes down any excess and obsolete inventories to their realizable value in the period in which the impairment is first identified. Shipping and handling costs incurred for inventory purchases are capitalized and recorded upon sale in cost of product revenues in the consolidated statements of operations and comprehensive loss or are included in the value of T2-owned instruments and components, a component of property and equipment, net, and depreciated. The Company capitalizes inventories in preparation for sales of products when the related product candidates are considered to have a high likelihood of regulatory clearance, which for the T2Dx Instrument and T2Candida Panel was upon the achievement of regulatory clearance, and the related costs are expected to be recoverable through sales of the inventories. In addition, the Company capitalizes inventories related to the manufacture of instruments that have a high likelihood of regulatory clearance, which for the T2Dx Instrument was upon the achievement of regulatory clearance, and will be retained as the Company’s assets, upon determination that the instrument has alternative future uses. In determining whether or not to capitalize such inventories, the Company evaluates, among other factors, information regarding the product candidate’s status of regulatory submissions and communications with regulatory authorities, the outlook for commercial sales and alternative future uses of the product candidate. Costs associated with development products prior to satisfying the inventory capitalization criteria are charged to research and development expense as incurred. The Company classifies inventories related to instruments that are Company-owned, as a component of property and equipment. Raw material and work-in-process inventories that are expected to be used to produce Company-owned instruments, based on our business model and forecast, are also classified as property and equipment. Company-owned instruments are instruments that are manufactured and placed with customers in connection with reagent rental agreements, or are used for internal purposes. The components of inventory consist of the following (in thousands): December 31, December 31, 2015 2014 Raw materials $ $ Work-in-process Finished goods — Total inventories $ $
Fair Value Measurements	Fair Value Measurements The Company is required to disclose information on all assets and liabilities reported at fair value that enables an assessment of the inputs used in determining the reported fair values. ASC 820, Fair Value Measurements and Disclosures (“ASC 820”), establishes a hierarchy of inputs used in measuring fair value that maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that the observable inputs be used when available. Observable inputs are inputs that market participants would use in pricing the asset or liability based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company’s assumptions about the inputs that market participants would use in pricing the asset or liability, and are developed based on the best information available in the circumstances. The fair value hierarchy applies only to the valuation inputs used in determining the reported fair value of the investments and is not a measure of the investment credit quality. The hierarchy defines three levels of valuation inputs: Level 1 — Quoted unadjusted prices for identical instruments in active markets. Level 2 — Quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, and model ‑derived valuations in which all observable inputs and significant value drivers are observable in active markets. Level 3 — Model derived valuations in which one or more significant inputs or significant value drivers are unobservable, including assumptions developed by the Company. The fair value hierarchy prioritizes valuation inputs based on the observable nature of those inputs. Assets and liabilities measured at fair value are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires management to make judgments and consider factors specific to the asset or liability (See Note 3). Financial instruments measured at fair value on a recurring basis include cash, money market funds and restricted cash (See Note 3). For certain financial instruments, including accounts payable and accrued expenses, the carrying amounts approximate their fair values as of December 31, 2015 and 2014 because of their short-term nature. At December 31, 2015 and 2014, the carrying value of the Company’s debt approximated fair value, which was determined using Level 3 inputs, including a quoted interest rate (Note 6).
Property and Equipment	Property and Equipment Property and equipment are recorded at cost and depreciated over their estimated useful lives using the straight ‑line method. Property and equipment includes raw materials, work-in-process and finished instruments that are Company-owned or expected to remain Company-owned when placed in service. Company-owned instruments are instruments that are manufactured and placed with customers in connection with reagent rental agreements, or are used for internal purposes. Repairs and maintenance costs are expensed as incurred, whereas major improvements are capitalized as additions to property and equipment.
Revenue Recognition	Revenue Recognition The Company generates revenue from product sales, which includes the sale of T2Dx, consumable diagnostic tests and related services, and research and development agreements with third parties. The Company recognizes revenue in accordance with FASB ASC Topic 605, Revenue Recognition (“ASC 605”). Accordingly, the Company recognizes revenue when all of the following criteria have been met: i. Persuasive evidence of an arrangement exists ii. Delivery has occurred or services have been rendered iii. The seller’s price to the buyer is fixed or determinable iv. Collectability is reasonably assured If any of the above criteria have not been met, the Company defers revenue until such time each of the criteria have been satisfied. Product revenue is generated by the sale of T2Dx and consuma ble diagnostic tests. The Company either sells T2Dx to customers, or retains title and places a T2Dx at the customer site pursuant to a reagent rental agreement. When a T2Dx is directly purchased by a customer, the Company recognizes revenue when all applicable revenue recognition criteria are met. When a T2Dx is placed under a reagent rental agreement, the Company’s customers generally agree to long-term agreements, certain of which may include minimum purchase commitments and/or incremental charge s on each consumable diagnostic test purchased, which varies based on the monthly volume of test cartridges purchased. Revenue from the sale of consumable diagnostic tests, which includes the incremental charge, is recognized upon delivery as a component of product revenue in the Company’s consolidated statements of operations and comprehensive loss. Direct sales of T2Dx include warranty, maintenance and technical support services for one year following the installation of the purchased T2Dx (“Maintenance Se rvices”). After the completion of the initial Maintenance Services period, customers have the option to renew the Maintenance Services for additional one year periods in exchange for additional consideration. In addition, the Company may provide training to customers. The Company defers revenue from the initial sale of T2Dx equal to the relative fair value of the one year of Maintenance Services and training and recognizes the amounts ratably over the service delivery period. The Company warrants that consumable diagnostic tests will be free from defects, when handled according to product specifications, for the stated life of the product. To fulfill valid warranty claims, the Company provides a credit to its customers on future orders. Accordingly, the Company defers revenue associated with the estimated defect rates of the consumable diagnostic tests. The Company does not offer rights of return for T2Dx or consumable diagnostic tests. Shipping and handling costs incurred associated with products sold to customers are recorded as a cost of product revenue in the consolidated statement of operations and comprehensive loss. Shipping and handling costs billed to customers in connection with a product sale are recorded as a component of product revenue in the consolidated statements of operations and comprehensive loss. For multiple-element arrangements, the Company identifies the deliverables included within each agreement and evaluates which deliverables represent separate units of accounting. The determination that multiple elements in an arrangement meet the criteria for separate units of accounting requires the Company’s management to exercise judgment. The Company accounts for those components as separate elements when the following criteria are met: (1) the delivered items have value to the customer on a stand-alone basis; and, (2) if there is a general right of return relative to the delivered items, delivery or performance of the undelivered items is considered probable and within its control. The consideration received is allocated among the separate units of accounting based on a selling price hierarchy. The selling price hierarchy is based on: (1) vendor specific objective evidence (“VSOE”), if available; (2) third party evidence of selling price if VSOE is not available; or (3) best estimated selling price (“BESP”) if neither VSOE nor third party evidence is available. The Company generally expects that it will not be able to establish selling price using third-party evidence due to the nature of our products and the markets in which the Company compete s , and, as such, the Company typically will determine selling price using VSOE or BESP. When the Company establishes selling price using BESP, consideration is given to both market and Company-specific factors, including the cost to produce the deliverable and the anticipated margin on that deliverable, as well as the characteristics of markets in which the deliverable is sold. Revenue earned from activities performed pursuant to research and development agreements is reported as research revenue in the consolidated statements of operations and comprehensive loss, using the proportional performance method as the work is completed, limited to payments earned, and the related costs are expensed as incurred as research and development expense. The timing of receipt of cash from the Company’s research and development agreements generally differs from when revenue is recognized.
Cost of Product Revenue	Cost of Product Revenue Cost of product revenue includes the cost of materials, direct labor and manufacturing overhead costs used in the manufacture of consumable diagnostic tests sold to customers and related license and royalty fees. Cost of product revenue also includes depreciation on revenue generating T2Dx that have been placed with customers under reagent rental agreements; costs of materials, direct labor and manufacturing overhead costs on T2Dx sold to customers; and other costs such as customer support costs, royalties and license fees, warranty and repair and maintenance expense on T2Dx that have been placed with customers under reagent rental agreements.
Research and Development Costs	Research and Development Costs Costs incurred in the research and development of the Company’s product candidates are expensed as incurred. Research and development expenses consist of costs incurred in performing research and development activities, including activities associated with performing services under research revenue arrangements, and include salaries and benefits, stock compensation, research ‑related facility and overhead costs, laboratory supplies, equipment and contract services.
Impairment of Long Lived Assets	Impairment of Long Lived Assets The Company reviews long ‑lived assets, including capitalized T2 owned equipment and components , for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. During this review, the Company reevaluates the significant assumptions used in determining the original cost and estimated lives of long ‑lived assets. Although the assumptions may vary from asset to asset, they generally include operating results, changes in the use of the asset, cash flows and other indicators of value. Management then determines whether the remaining useful life continues to be appropriate or whether there has been an impairment of long ‑lived assets based primarily upon whether expected future undiscounted cash flows are sufficient to support the assets’ recovery. If impairment exists, the Company would adjust the carrying value of the asset to fair value, generally determined by a discounted cash flow analysis. No impairment charges have been recorded in any of the periods presented.
Comprehensive Loss	Comprehensive Loss Comprehensive loss is defined as the change in equity of a business enterprise during a period from transactions and other events and circumstances from non ‑owner sources. Comprehensive loss consists of net loss and other comprehensive loss, which includes certain changes in equity that are excluded from net loss. The Company’s comprehensive loss equals reported net loss for all periods presented.
Stock Based Compensation	Stock Based Compensation The Company has a stock ‑based compensation plan which is more fully described in Note 9. The Company records stock ‑based compensation for options granted to employees and to members of the board of directors for their services on the board of directors, based on the grant date fair value of awards issued, and the expense is recorded on a straight ‑line basis over the applicable service period, which is generally four years. The Company accounts for non ‑employee stock ‑based compensation arrangements based upon the fair value of the consideration received or the equity instruments issued, whichever is more reliably measurable. The measurement date for non ‑employee awards is generally the date that the performance of services required for the non ‑employee award is complete. Stock ‑based compensation costs for non ‑employee awards is recognized as services are provided, which is generally the vesting period, on a straight ‑line basis. The Company expenses restricted stock awards based on the fair value of the award on the date of issuance, on a straight ‑line basis over the associated service period of the award. The Company uses the Black ‑Scholes ‑Merton option pricing model to determine the fair value of stock options. The use of the Black ‑Scholes ‑Merton option ‑pricing model requires management to make assumptions with respect to the expected term of the option, the expected volatility of the common stock consistent with the expected life of the option, risk ‑free interest rates and expected dividend yields of the common stock. The expected term was determined according to the simplified method, which is the average of the vesting tranche dates and the contractual term. Due to the lack of a public market for the trading of the Company’s common stock and a limited amount of company ‑specific historical and implied volatility data, the Company base s its estimate of expected volatility primarily on the historical volatility of a group of similar companies that are publicly traded. For these analyses, companies with comparable characteristics a re selected, including enterprise value and position within the industry, and with historical share price information sufficient to meet the expected life of the stock ‑based awards. The Company compute s the historical volatility data using the daily closing prices for the selected companies’ shares during the equivalent period of the calculated expected term of its stock ‑based awards. The risk ‑free interest rate is determined by reference to U.S. Treasury zero ‑coupon issues with remaining maturities similar to the expected term of the options. The Company has not paid, and does not anticipate paying, cash dividends on shares of common stock; therefore, the expected dividend yield is assumed to be zero . The Company is required to estimate forfeitures at the time of grant and revise those estimates in subsequent periods if actual forfeitures differ from those estimates.
Income Taxes	Income Taxes The Company provides for income taxes using the liability method. The Company provides deferred tax assets and liabilities for the expected future tax consequences of temporary differences between the Company’s financial statement carrying amounts and the tax basis of assets and liabilities using enacted tax rates expected to be in effect in the years in which the differences are expected to reverse. A valuation allowance is provided to reduce the deferred tax assets to the amount that will more likely than not be realized. The Company applies ASC 740 Income Taxes (“ASC 740”) in accounting for uncertainty in income taxes. The Company does not have any material uncertain tax positions for which reserves would be required. The Company will recognize interest and penalties related to uncertain tax positions, if any, in income tax expense.
Guarantees	Guarantees As permitted under Delaware law, the Company indemnifies its officers and directors for certain events or occurrences while the officer or director is, or was, serving at the Company’s request in such capacity. The term of the indemnification is for the officer’s or director’s lifetime. The maximum potential amount of future payments the Company could be required to make is unlimited; however, the Company has directors’ and officers’ insurance coverage that limits its exposure and enables it to recover a portion of any future amounts paid. The Company leases office, laboratory and manufacturing space under noncancelable operating leases. The Company has standard indemnification arrangements under the leases that require it to indemnify the landlord against all costs, expenses, fines, suits, claims, demands, liabilities, and actions directly resulting from any breach, violation or nonperformance of any covenant or condition of the Company’s leases. As of December 31, 2015 and 2014, the Company had not experienced any material losses related to these indemnification obligations, and no material claims with respect thereto were outstanding. The Company does not expect significant claims related to these indemnification obligations and, consequently, concluded that the fair value of these obligations is negligible, and no related reserves were established.
Net Loss Per Share	Net Loss Per Share Basic net loss per share is calculated by dividing net loss applicable to common stockholders by the weighted ‑average number of shares outstanding during the period, without consideration for common stock equivalents. Diluted net loss per share is calculated by adjusting the weighted ‑average number of shares outstanding for the dilutive effect of common stock equivalents outstanding for the period, determined using the treasury ‑stock method. For purposes of the diluted net loss per share calculation, redeemable convertible preferred stock, and warrants to purchase redeemable convertible preferred stock, which were outstanding prior to the Company’s IPO, and stock options and unvested restricted stock are considered to be common stock equivalents, but have been excluded from the calculation of diluted net loss per share, as their effect, including the related impact to the numerator of the fair value adjustment of the warrants and the impact to the denominator of the warrant shares, would be anti ‑dilutive for all periods presented. Therefore, basic and diluted net loss per share applicable to common stockholders were the same for all periods presented.
Recently Issued Accounting Pronouncements	Recently Issued Accounting Pronouncements From time to time, new accounting pronouncements are issued by the FASB or other standard setting bodies and adopted by the Company as of the specified effective date. Unless otherwise discussed, the Company believes that the impact of recently issued standards that are not yet effective will not have a material impact on its financial position or results of operations upon adoption. In February 2016, the FASB issued ASU No. 2016-02, Leases (“ASU 2016-02”), which applies to all leases and will require lessees to put most leases on the balance sheet, but recognize expense in a manner similar to the current standard. ASU 2016-02 is effective for fiscal years beginning after December 15, 2018 and interim periods within those years, which is the year ended December 31, 2019 for the Company. Entities are required to use a modified retrospective approach of adoption for leases that exist or are entered into after the beginning of the earliest comparative period in the financial statements. Full restrospective application is prohibited. The Company is evaluating the new guidance and the expected effect on the Company’s consolidated financial statements. In November 2015, the FASB issued ASU No. 2015-17, Balance Sheet Classification of Deferred Taxes (“ASU 2015-17”). The standard requires all companies to report deferred tax assets and liabilities as noncurrent, which modifies the current standard, which requires deferred tax assets and liabilities to be classified as current or noncurrent based on how the related assets or liabilities are classified. ASU 2015-17 is effective for fiscal years beginning after December 15, 2015, and for interim periods within those annual periods. Early adoption is permitted and may be applied prospectively or retrospectively. The Company has adopted ASU 2015-17 as of December 31, 2015 on a prospective basis, which resulted the netting of deferred tax assets and liabilities on the consolidated balance sheet. In July 2015, the FASB issued ASU No. 2015-11, Inventory (Topic 330): Simplifying the Measurement of Inventory (“ASU 2015-11”). The standard simplifies the subsequent measurement of inventory by requiring inventory to be measured at the lower of cost and net realizable value for entities using the first-in-first out method of valuing inventory. ASU 2015-11 eliminates other measures required by current guidance to determine net realizable value. ASU 2015-11 is effective for fiscal years beginning after December 15, 2016 and interim periods within those fiscal years and early adoption is permitted. The Company has not adopted ASU 2015-11 and does not expect the new guidance to have a material effect on its consolidated financial statements. In April 2015, the FASB issued ASU No. 2015-05, Customer’s Accounting for Fees Paid in a Cloud Computing Arrangement (“ASU 2015-05”). The standard clarifies that customers in cloud computing arrangements should determine whether the arrangement includes a license of software by applying the same guidance as cloud service providers and eliminates the existing requirement for customers to account for software licenses acquired by analogizing to the guidance on leases. It is effective for annual periods beginning on or after December 15, 2015, including interim periods within those annual periods, and early adoption is permitted. Adoption of ASU 2015-05 can either be applied (1) prospectively to all arrangements entered into or materially modified after the effective date or (2) retrospectively. The Company has not adopted the guidance prescribed by ASU 2015-05 and does not expect the new guidance to have a material effect on its consolidated financial statements. In April 2015, the FASB issued ASU No. 2015-03, Simplifying the Presentation of Debt Issuance Costs (“ASU 2015-03”). This standard amends existing guidance to require the presentation of debt issuance costs in the balance sheet as a deduction from the carrying amount of the related debt liability instead of a deferred charge. It is effective for annual reporting periods beginning after December 15, 2015, but early adoption is permitted. Adoption of ASU 2015-03 is applied retrospectively. The Company has not adopted the guidance prescribed by ASU 2015-03. However, had the Company adopted this guidance as of December 31, 2015, the Company would reclassify a total of $151,000 of deferred financing costs from other current assets and other assets on the consolidated balance sheet and reduce the total notes payable balance accordingly. In June 2014, the FASB issued amended guidance, ASU No. 2014-09, Revenue from Contracts with Customers (“ASU 2014-09”), which is applicable to revenue recognition that will now be effective for the Company for the year ending December 31, 2018, as a result of the deferral of the effective date adopted by the FASB in July 2015. The new guidance must be adopted using either a full retrospective approach for all periods presented or a modified retrospective approach. Early adoption prior to the original adoption date of ASU 2014-09 is not permitted. The new guidance applies a more principles-based approach to revenue recognition. The Company is evaluating the new guidance and the expected effect on the Company’s consolidated financial statements. In 2014, the FASB issued ASU 2014-15, Presentation of Financial Statements – Going Concern (“ASU 2014-15”), which is effective for annual periods ending after December 15, 2016. Early adoption is permitted. ASU 2014-15 provides new guidance on (1) management’s responsibility in evaluating whether or not there is substantial doubt about a company’s ability to continue as a going concern within one year from the date the financial statements are issued each reporting period and (2) related financial statement disclosures. The Company has not adopted the guidance prescribed by ASU 2014-15. However, had the Company applied the guidance prescribed by ASU 2014-15 as of December 31, 2015, the Company would determine that there is not substantial doubt about its ability to continue as a going concern for at least one year from date the financial statements are issued .

Summary of Significant Accoun25

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2015
Summary of Significant Accounting Policies
Schedule of inventory	The components of inventory consist of the following (in thousands): December 31, December 31, 2015 2014 Raw materials $ $ Work-in-process Finished goods — Total inventories $ $

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2015
Fair Value Measurements
Schedule of financial assets and liabilities at fair value on a recurring basis	The following tables set forth the Company’s financial assets and liabilities carried at fair value categorized using the lowest level of input applicable to each financial instrument as of December 31, 2015 and 2014 (in thousands): Quoted Prices in Active Significant Markets for Other Significant Balance at Identical Observable Unobservable December 31, Assets Inputs Inputs 2015 (Level 1) (Level 2) (Level 3) Assets: Cash $ $ $ — $ — Money market funds — — Restricted cash — — $ $ $ — $ — Quoted Prices in Active Significant Markets for Other Significant Balance at Identical Observable Unobservable December 31, Assets Inputs Inputs 2014 (Level 1) (Level 2) (Level 3) Assets: Cash $ $ $ — $ — Money market funds — — Restricted cash — — $ $ $ — $ —

Supplemental Balance Sheet In27

Supplemental Balance Sheet Information (Tables)	12 Months Ended
	Dec. 31, 2015
Supplemental Balance Sheet Information.
Schedule of property and equipment	Property and equipment consists of the following (in thousands) Estimated Useful December 31, Life (Years) 2015 2014 Office and computer equipment 3 $ $ Software 3 Laboratory equipment 5 Furniture 5 - 7 Manufacturing equipment 5 — Manufacturing tooling and molds 0.5 T2 instruments and components 5 Leasehold improvements Lesser of useful life or lease term Construction in progress n/a Less accumulated depreciation and amortization Property and equipment, net $ $
Components of accrued expenses	Accrued expenses consist of the following (in thousands): December 31, 2015 2014 Accrued payroll and compensation $ $ Accrued research and development expenses Accrued professional services Other accrued expenses Total accrued expenses $ $

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2015
Debt
Summary of future principal payments on the notes payable	Future principal payments on the notes payable as of December 31, 2015 are as follows (in thousands): Year ended December 31, 2016 $ 2017 2018 2019 Total debt payments Less current portion (principal) Less debt discount Notes payable, net of current portion $

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2015
Stock Based Compensation
Summary of stock option activity	The following is a summary of option activity under the Plan (in thousands, except share and per share amounts): Weighted-Average Weighted-Average Remaining Number of Exercise Price Per Contractual Term Aggregate Intrinsic Shares Share (In years) Value Outstanding at December 31, 2014 $ $ Granted Exercised Cancelled Outstanding at December 31, 2015 Exercisable at December 31, 2015 Vested or expected to vest at December 31, 2015
Schedule of estimated assumptions used to calculate weighted-average fair value of options granted	Year ended December 31, 2015 2014 2013 Weighted-average risk-free interest rate % % % Expected dividend yield % % % Expected volatility % % % Expected terms years years years
Summary of stock-based compensation expense for stock options granted that was recorded in the Company's results of operations	The following table summarizes the stock-based compensation expense for stock options granted to employees and non-employees, as well as stock-compensation expense for the 2014 ESPP that was recorded in the Company’s results of operations for the years presented (in thousands): Year ended December 31, 2015 2014 2013 Research and development $ $ $ Selling, general and administrative Total stock-based compensation expense $ $ $

Net Loss Per Share (Tables)

Net Loss Per Share (Tables)	12 Months Ended
	Dec. 31, 2015
Net Loss Per Share
Schedule of basic and diluted net loss per share applicable to common stockholders	The following table presents the calculation of basic and diluted net loss per share applicable to common stockholders (in thousands, except share and per share data): Year ended December 31, 2015 2014 2013 Numerator: Net loss $ $ $ Accretion of redeemable convertible preferred stock to redemption value — Net loss applicable to common stockholders $ $ $ Denominator: Weighted-average number of common shares outstanding — basic and diluted Net loss per share applicable to common stockholders — basic and diluted $ $ $
Schedule of shares excluded from the calculation where the inclusion would be anti-dilutive	Year ended December 31, 2015 2014 2013 Redeemable convertible preferred stock — — Options to purchase common shares Warrants to purchase redeemable convertible preferred stock — — Total

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2015
Income Taxes
Schedule of reconciliation of the U.S. federal statutory rate to the Company?s effective tax rate	Year Ended December 31, 2015 2014 2013 Tax at statutory rates % % % State income taxes Permanent differences Research and development credits Change in valuation allowance Effective tax rate % % %
Schedule of Deferred Tax Assets	The significant components of the Company’s deferred tax asset consist of the following at December 31, 2015 and 2014 (in thousands): December 31, 2015 2014 Deferred tax assets: Net operating loss carryforwards $ $ Tax credits Other temporary differences Start-up expenditures Stock option expenses Total deferred tax assets Deferred tax asset valuation allowance Net deferred tax assets Deferred tax liabilities: Prepaid expenses Net deferred taxes $ — $ —

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2015
Commitments and Contingencies.
Schedule of future minimum lease payments under the Company?s operating leases	Future minimum non-cancelable lease payments under the Company’s operating leases are as follows (in thousands): Year ending December 31, 2016 $ 2017 2018 2019 2020 Thereafter $

Quarterly Financial Data (una33

Quarterly Financial Data (unaudited) (Tables)	12 Months Ended
	Dec. 31, 2015
Quarterly Financial Data (unaudited)
Schedule of quarterly financial information	Year ended December 31, 2015 (In thousands, except per share data) First Quarter Second Quarter Third Quarter Fourth Quarter Revenue: Product revenue $ $ — $ $ Research revenue Total revenue $ $ $ $ Costs and expenses: Cost of product revenue — Research and development Selling, general and administrative Total costs and expenses Loss from operations $ $ $ $ Net loss $ $ $ $ Net loss applicable to common shareholders $ $ $ $ Per share data: Net loss per common share—basic and diluted $ $ $ $ Year ended December 31, 2014 (In thousands, except per share data) First Quarter Second Quarter Third Quarter Fourth Quarter Revenue: Product revenue $ — $ — $ — $ — Research revenue — — — Total revenue $ — $ — $ — $ Costs and expenses: Cost of product revenue — — — — Research and development Selling, general and administrative Total costs and expenses Loss from operations $ $ $ $ Net loss $ $ $ $ Net loss applicable to common shareholders $ $ $ $ Per share data: Net loss per common share—basic and diluted $ $ $ $

Nature of Business (Details)

Nature of Business (Details) - USD ($) $ in Thousands	Aug. 12, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash and cash equivalents		$ 73,662	$ 73,849	$ 30,198	$ 9,709
Accumulated deficit		(148,885)	$ (103,595)
Period over which cash resources will be sufficient to allow Company to fund current operating plan	12 months
Note Agreement 1
Remaining borrowing capacity		$ 10,000

Summary of Significant Accoun35

Summary of Significant Accounting Policies (Details)	12 Months Ended
	Dec. 31, 2015USD ($)segmentitem	Dec. 31, 2014USD ($)item	Dec. 31, 2013USD ($)
Segment Information
Number of Operating Segments | segment	1
Off Balance Sheet Risk and Concentrations of Credit Risk
Number of financial institutions in which cash was deposited | item	1	1
Inventory
Raw materials	$ 203,000	$ 71,000
Work-in-process	287,000	44,000
Finished goods	193,000
Total inventories	683,000	115,000
Impairment of Long Lived Assets
Impairment charges	$ 0	$ 0	$ 0
Stock Based Compensation
Vesting period	4 years
Expected dividend yield	0.00%
Debt issuance costs
Debt issuance costs deferred	$ 151,000
Customer One
Off Balance Sheet Risk and Concentrations of Credit Risk
Total revenue (as a percent)	50.00%
Customer Two
Off Balance Sheet Risk and Concentrations of Credit Risk
Total revenue (as a percent)	25.00%

Summary of Significant Accoun36

Summary of Significant Accounting Policies Product Service (Details) - T2Dx	12 Months Ended
	Dec. 31, 2015
Product information
Maintenance Services period (in years)	1 year
Additional period for Maintenance Service option (in years)	1 year

Fair Value Measurements - Finan

Fair Value Measurements - Financial assets and liabilities at fair value (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Fair value measurements
Transfers of assets from level 1 to 2	$ 0	$ 0
Transfers of assets from level 2 to 1	0	0
Transfer of liabilities from level 1 to 2	0	0
Transfer of liabilities from level 2 to 1	0	0
Transfer of liabilities to or from level 3	0	0
Recurring | Total
Assets:
Restricted cash	260	340
Total assets	73,922	74,189
Recurring | Total | Cash
Assets:
Cash and cash equivalents	1,520	10,348
Recurring | Total | Money market funds
Assets:
Cash and cash equivalents	72,142	63,501
Recurring | Level I | Total
Assets:
Restricted cash	260	340
Total assets	73,922	74,189
Recurring | Level I | Total | Cash
Assets:
Cash and cash equivalents	1,520	10,348
Recurring | Level I | Total | Money market funds
Assets:
Cash and cash equivalents	$ 72,142	$ 63,501

Restricted Cash (Details)

Restricted Cash (Details) - Certificates of deposit - USD ($)	1 Months Ended
	Jun. 30, 2015	Dec. 31, 2015	Dec. 31, 2014
Restricted cash
Security deposit for operating lease	$ 240,000	$ 260,000	$ 340,000
Decrease in security deposit	$ (80,000)

Supplemental Balance Sheet In39

Supplemental Balance Sheet Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Property and Equipment
Property and equipment, gross	$ 15,462,000	$ 6,102,000
Accumulated depreciation and amortization	(4,807,000)	(3,342,000)
Property and equipment, net	10,655,000	2,760,000
Depreciation and amortization	1,465,000	691,000	$ 584,000
Accrued expenses
Accrued payroll and compensation	2,418,000	1,846,000
Accrued research and development expenses	458,000	733,000
Accrued professional services	542,000	374,000
Other accrued expenses	744,000	709,000
Total accrued expenses	$ 4,162,000	3,662,000
Office and computer equipment
Property and Equipment
Estimated useful lives (Years)	3 years
Property and equipment, gross	$ 395,000	383,000
Software
Property and Equipment
Estimated useful lives (Years)	3 years
Property and equipment, gross	$ 632,000	480,000
Laboratory equipment
Property and Equipment
Estimated useful lives (Years)	5 years
Property and equipment, gross	$ 4,112,000	3,312,000
Furniture
Property and Equipment
Property and equipment, gross	$ 187,000	187,000
Furniture | Minimum
Property and Equipment
Estimated useful lives (Years)	5 years
Furniture | Maximum
Property and Equipment
Estimated useful lives (Years)	7 years
Manufacturing equipment
Property and Equipment
Estimated useful lives (Years)	5 years
Property and equipment, gross	$ 577,000
Manufacturing tooling and molds
Property and Equipment
Estimated useful lives (Years)	6 months
Property and equipment, gross	$ 71,000	26,000
T2 instruments and components
Property and Equipment
Estimated useful lives (Years)	5 years
Property and equipment, gross	$ 4,960,000	563,000
Depreciation expense recorded as a component of cost of product revenue	$ 105,000
T2 Owned Instruments in Service
Property and Equipment
Estimated useful lives (Years)	5 years
Property and equipment, gross	$ 1,900,000
Leasehold improvements
Property and Equipment
Property and equipment, gross	3,332,000	764,000
Construction in progress
Property and Equipment
Property and equipment, gross	$ 1,196,000	$ 387,000

Debt (Details)

Debt (Details)	Dec. 28, 2015USD ($)	Jul. 11, 2014USD ($)trancheLender	May. 31, 2015USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)	Dec. 31, 2012USD ($)	Dec. 31, 2012USD ($)	Jun. 25, 2012USD ($)installment	May. 09, 2011USD ($)
Debt Instrument [Line Items]
Proceeds from issuance of note payable, net				$ 10,000,000	$ 19,714,000
Repayments of Notes Payable				309,000	4,037,000	$ 848,000
Interest Expense				2,000,000	741,000	410,000
Non-cash interest				354,000	112,000	$ 44,000
Note Agreement 1
Debt Instrument [Line Items]
Number of lenders | Lender		2
Maximum borrowings available		$ 30,000,000
Number of tranches | tranche		2
Remaining borrowing capacity				10,000,000
Proceeds from issuance of note payable, net				$ 29,700,000
Interest rate including both the variable rate and the basis spread (as a percent)				7.28%
Final fee as a percentage of original principal amount of amounts borrowed		4.75%
Minimum amount of denomination for prepayment of borrowings		$ 1,000,000
Effective interest rate including final fee interest and non-cash interest (as a percent)				9.70%
Note Agreement 1 | Prior to second anniversary and after first anniversary of borrowing date
Debt Instrument [Line Items]
Prepayment premium (as a percent)		1.00%
Note Agreement 1 | Prior to maturity date and after second anniversary of borrowing date
Debt Instrument [Line Items]
Prepayment premium (as a percent)		0.50%
Note Agreement 1 | LIBOR
Debt Instrument [Line Items]
Variable Interest Rate		one-month LIBOR
Basis spread (as a percent)		7.05%
Note Agreement 1 | Tranche A
Debt Instrument [Line Items]
Maximum borrowings available		$ 20,000,000
Minimum amount of draw upon closing		10,000,000
Minimum amount of draw after closing		5,000,000
Proceeds from issuance of debt					$ 20,000,000
Note Agreement 1 | Tranche B
Debt Instrument [Line Items]
Maximum borrowings available		10,000,000	$ 10,000,000
Commitment fee on undrawn principal (as a percent)			1.00%
Fee Amount	$ 50,000
Note Agreement 2
Debt Instrument [Line Items]
Maximum borrowings available									$ 4,500,000
Proceeds received on borrowings							$ 4,500,000
Stated interest rate (as a percent)									6.25%
Number of monthly principal installments | installment									36
Repayments of Notes Payable		$ 2,900,000
Note Agreement 2 | Prior to first anniversary of borrowing date
Debt Instrument [Line Items]
Prepayment premium (as a percent)									2.00%
Note Agreement 2 | Prior to second anniversary and after first anniversary of borrowing date
Debt Instrument [Line Items]
Prepayment premium (as a percent)									1.00%
Note Agreement 3
Debt Instrument [Line Items]
Maximum borrowings available										$ 1,700,000
Proceeds received on borrowings								$ 1,400,000
Stated interest rate (as a percent)										6.50%
Minimum cash balance										$ 300,000

Debt - Future principal payemen

Debt - Future principal payements on notes payable (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Future principal payments on the notes payable
2,016	$ 4,495
2,017	10,351
2,018	10,126
2,019	5,833
Total debt payments	30,805
Less current portion (principal)	(4,495)
Less debt discount	(88)
Notes payable, net of current portion	$ 26,222	$ 20,660

Redeemable Convertible Prefer42

Redeemable Convertible Preferred Stock (Details) - USD ($) $ in Thousands	Aug. 12, 2014	Dec. 31, 2014
Conversion of convertible preferred stock into common stock	$ 117,400
Conversion of redeemable convertible preferred stock into common stock		$ 117,383
Common Stock
Conversion of redeemable convertible preferred stock into common stock (in shares)	12,516,298	12,516,298
Conversion of redeemable convertible preferred stock into common stock		$ 13
Accumulated Deficit
Conversion of redeemable convertible preferred stock into common stock	$ 21,000	21,029
Additional Paid-in Capital
Conversion of redeemable convertible preferred stock into common stock	$ 96,300	$ 96,341

Stockholders' Equity (Deficit)

Stockholders' Equity (Deficit) (Details)	12 Months Ended
	Dec. 31, 2015itemshares
IPO
Common Stock Number Of Votes Per Share | item	1
Options to purchase common shares
IPO
Common stock were reserved for issuance	3,484,298
2014 Incentive Award Plan and 2014 Employee Stock Purchase Plan
IPO
Common stock were reserved for issuance	552,024

Stock Based Compensation (Detai

Stock Based Compensation (Details) - USD ($)	Aug. 12, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-Based Compensation
Vesting period		4 years
Fair value assumptions
Stock-based compensation expense		$ 4,053,000	$ 1,653,000	$ 578,000
Employee Stock Purchase Plan
Share-Based Compensation
Shares available for grant		156,891
Number of shares issued under the plan
Shares available for authorized		220,588
Fair value assumptions
Percentage of full share price paid in purchase of common stock		85.00%
Maximum amount of annual employee common stock purchases		$ 25,000
Stock-based compensation expense		233,000	103,000
Percentage of shares outstanding	1.00%
2006 and 2014 Stock Option Plans | Options to purchase common shares
Share-Based Compensation
Aggregate fair value of options granted		$ 10,100,000	$ 6,000,000	$ 2
Number of Shares
Outstanding, beginning of the period (in shares)		2,911,146
Granted (in shares)		1,194,483
Exercised (in shares)		(378,991)
Cancelled (in shares)		(242,340)
Outstanding, end of the period (in shares)		3,484,298	2,911,146
Exercisable (in shares)		1,730,186
Vested or expected to vest (in shares)		3,323,663
Weighted Average Exercise Price Per Share
Outstanding, beginning of the period (in dollars per share)		$ 5.30
Granted (in dollars per share)		15.86
Exercised (in dollars per share)		2.95
Cancelled (in dollars per share		10.87
Outstanding, end of the period (in dollars per share)		8.79	$ 5.30
Exercisable (in dollars per share)		5.17
Vested or expected to vest (in dollars per share)		$ 8.58
Weighted-Average Remaining Contractual Term (in years)
Outstanding (in years)		7 years 7 months 21 days	7 years 10 months 13 days
Exercisable (in years)		6 years 4 months 2 days
Vested or expected to vest (in years)		7 years 6 months 26 days
Aggregate Intrinsic Value
Outstanding, beginning of the period		$ 40,586,000
Exercised (in dollars)		4,513,000
Outstanding, end of the period		14,620,000	$ 40,586,000
Exercisable		11,648,000
Vested or expected to vest		$ 14,450,000
Fair value assumptions
Weighted average fair value of options granted (in dollars per share)		$ 8.42	$ 7.59	$ 1.85
Weighted-average risk-free interest rate		1.69%	1.91%	1.68%
Expected dividend yield		0.00%	0.00%	0.00%
Expected volatility		56.00%	61.00%	63.00%
Expected terms		6 years	5 years 10 months 24 days	6 years
Fair value of stock options vested		$ 4,000,000	$ 1,200,000	$ 476,000
2006 Stock Option Plan | Maximum | Options to purchase common shares
Share-Based Compensation
Expiration Period		10 years
Vesting period		4 years
2014 Stock Option Plan | Options to purchase common shares
Share-Based Compensation
Shares available for future issuance under stock incentive plan		823,529
Percentage of common shares outstanding		4.00%
Shares available for grant		395,133
2014 Stock Option Plan | Maximum | Options to purchase common shares
Share-Based Compensation
Expiration Period		10 years
Vesting period		4 years

Stock Based Compensation - Stoc

Stock Based Compensation - Stock-Based Compensation Expense (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Stock-based compensation expense
Stock-based compensation expense	$ 4,053,000	$ 1,653,000	$ 578,000
Stock based compensation expense included cost of product revenue	48,000
Stock based compensation expense included capitalized of inventory	67,000
Total unrecognized compensation costs related to non-vested stock options	$ 11,300,000
Remaining weighted-average period that unrecognized compensation costs are expected to be recognized	2 years 10 months 28 days
Research and development
Stock-based compensation expense
Stock-based compensation expense	$ 1,213,000	501,000	169,000
Selling, general and administrative
Stock-based compensation expense
Stock-based compensation expense	$ 2,840,000	$ 1,152,000	$ 409,000

Warrants (Details)

Warrants (Details) - IPO	Aug. 12, 2014shares
Class of Warrant or Right [Line Items]
Number of warrants outstanding	250,727
Issuance of common stock upon net settlement of warrants to purchase redeemable convertible preferred stock (in shares)	68,700

Net Loss Per Share (Details)

Net Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Numerator:
Net loss	$ (12,032)	$ (11,644)	$ (10,995)	$ (10,619)	$ (9,076)	$ (8,091)	$ (7,303)	$ (6,920)	$ (45,290)	$ (31,390)	$ (20,610)
Accretion of redeemable convertible preferred stock to redemption value										(4,570)	(6,908)
Net loss applicable to common stockholders	$ (12,032)	$ (11,644)	$ (10,995)	$ (10,619)	$ (9,076)	$ (8,849)	$ (9,209)	$ (8,826)	$ (45,290)	$ (35,960)	$ (27,518)
Denominator:
Weighted average number of common shares outstanding - basic and diluted									20,501,748	8,674,931	1,395,562
Net loss per share applicable to common stockholders - basic and diluted	$ (0.56)	$ (0.57)	$ (0.54)	$ (0.53)	$ (0.45)	$ (0.71)	$ (6.35)	$ (6.25)	$ (2.21)	$ (4.15)	$ (19.72)
Anti-dilutive securities excluded from the computation of diluted net loss per share (in shares)									3,484,298	2,911,146	14,929,755
Redeemable convertible preferred stock
Denominator:
Anti-dilutive securities excluded from the computation of diluted net loss per share (in shares)											12,516,298
Options to purchase common shares
Denominator:
Anti-dilutive securities excluded from the computation of diluted net loss per share (in shares)									3,484,298	2,911,146	2,265,973
Warrants to purchase redeemable convertible preferred stock
Denominator:
Anti-dilutive securities excluded from the computation of diluted net loss per share (in shares)											147,484

Income Taxes (Details)

Income Taxes (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Effective Income Tax Rate Reconciliation, Percent.
Tax at statutory rates	35.00%	35.00%	35.00%
State income taxes	6.60%	5.10%	5.20%
Permanent differences	(1.30%)	(0.80%)	(0.70%)
Research and development credits	1.50%	1.90%	2.30%
Change in valuation allowance	(41.80%)	(41.20%)	(41.80%)
Effective tax rate	0.00%	0.00%	0.00%
Deferred tax assets:
Net operating loss carryforwards	$ 49,417,000	$ 33,690,000
Tax credits	4,107,000	2,795,000
Other temporary differences	1,623,000	1,159,000
Startup expenditures	5,288,000	4,948,000
Stock option expenses	1,649,000	588,000
Total deferred tax assets	62,084,000	43,180,000
Deferred tax asset valuation allowance	(61,813,000)	(42,867,000)
Net deferred tax assets	271,000	313,000
Deferred tax liabilities:
Prepaid expenses	(271,000)	(313,000)
Increase in valuation allowance	18,900,000	12,700,000	$ 9,100,000
Unrecognized tax benefits	0
Accrued interest or penalties related to uncertain tax positions	0	$ 0
Federal
Deferred tax liabilities:
Net operating losses	126,700,000
Tax benefits from the exercise of stock options	2,400,000
Federal | Research and Development Member
Deferred tax liabilities:
Credit carryforward	2,800,000
State
Deferred tax liabilities:
Net operating losses	115,800,000
Tax benefits from the exercise of stock options	2,200,000
State | Research and Development Member
Deferred tax liabilities:
Credit carryforward	$ 1,500,000

Commitments and Contingencies49

Commitments and Contingencies (Details) - USD ($)	1 Months Ended				12 Months Ended			24 Months Ended
	May. 31, 2015	Nov. 30, 2014	May. 31, 2013	Aug. 31, 2010	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2007	Jan. 01, 2011	Dec. 31, 2006
Future minimum lease payments
2,016					$ 1,986,000
2,017					2,031,000
2,018					404,000
2,019					414,000
2,020					425,000
Thereafter					107,000
Total					5,367,000
Rent expenses					1,600,000	$ 950,000	$ 628,000
Operating lease entered into August 2010 | Office and laboratory space
Operating Leased Assets [Line Items]
Term of lease				5 years
Security deposit	$ 240,000								$ 400,000
Decrease in security deposit	$ 80,000
Operating lease entered into May 2013 | Office, laboratory and manufacturing space
Operating Leased Assets [Line Items]
Term of lease			2 years
Operating lease entered into November 2014 | Laboratory Space
Operating Leased Assets [Line Items]
Term of lease		6 years
Security deposit		$ 281,000
Space build-out costs paid		1,400,000
Space build-out costs to be paid by landlord		$ 2,200,000
License Agreement
License agreement
Payment of license fees and reimbursed patent costs					34,000	$ 345,000
Shares issued								84,678
Amount receivable for achievement of regulatory milestones					$ 300,000
License Agreement | Minimum
License agreement
License Fees Payable										$ 5,000
License Agreement | Maximum
License agreement
License Fees Payable										$ 25,000
License Agreement | Operating lease entered into November 2014 | Office Space
Operating Leased Assets [Line Items]
Term of lease		2 years
Security deposit		$ 50,000

Commitments and Contingencies E

Commitments and Contingencies Equipment Lease Facility (Details) - Equipment lease facility $ in Millions	1 Months Ended
	Oct. 31, 2015USD ($)
Capital lease obligation
Maximum borrowings available	$ 10
Debt term (in months)	36 months
Repurchase price as percentage of original equipment value that the equipment under lease may be repurchased by lessee	10.00%
Minimum
Capital lease obligation
Renewal term (in years)	1 year

401(k) Savings Plan (Details)

401(k) Savings Plan (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
401(k) Savings Plan
Contributions to 401 (k) plan at the discretion of the board	$ 0	$ 0

Co-Development Agreement with52

Co-Development Agreement with Canon US Life Sciences (Details) $ in Thousands	Feb. 03, 2015USD ($)item	Dec. 31, 2015USD ($)item	Sep. 30, 2015USD ($)	Jun. 30, 2015USD ($)	Mar. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2015USD ($)item	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)	Oct. 31, 2015USD ($)
Co-Development Agreement with Canon US Life Sciences
Revenues		$ 1,011	$ 1,049	$ 564	$ 189	$ 119	$ 2,813	$ 119	$ 266
Co Development Partnership Agreement | Canon U.S. Life Sciences Inc.
Co-Development Agreement with Canon US Life Sciences
Upfront payment received	$ 2,000
Additional consideration receivable upon achievement of certain development and regulatory milestones	6,500
Aggregate consideration receivable	$ 8,500
Consideration eligible to receive upon achievement of specified technical requirement related to the achievement of the milestone										$ 1,500
Additional consideration receivable upon achievement of additional development and regulatory milestones		$ 5,000					$ 5,000
Number of milestone payments | item		2					2
Additional consideration receivable upon achievement of development and regulatory milestones, payment one		$ 2,000					$ 2,000
Additional consideration receivable upon achievement of development and regulatory milestones, payment two		$ 3,000					3,000
Number of units | item	1
Revenues							$ 1,400

Quarterly Financial Data (una53

Quarterly Financial Data (unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenue:
Product revenue	$ 343	$ 245		$ 11					$ 599
Research revenue	668	804	$ 564	178	$ 119				2,214	$ 119	$ 266
Total revenue	1,011	1,049	564	189	119				2,813	119	266
Costs and expenses:
Cost of product revenue	910	829		1					1,740
Research and development	6,638	6,204	6,651	5,869	5,210	$ 4,803	$ 4,703	$ 5,066	25,362	19,782	14,936
Selling, general and administrative	5,008	5,181	4,437	4,468	3,747	2,984	2,446	1,841	19,094	11,018	5,022
Total costs and expenses	12,556	12,214	11,088	10,338	8,957	7,787	7,149	6,907	46,196	30,800	19,958
Loss from operations	(11,545)	(11,165)	(10,524)	(10,149)	(8,838)	(7,787)	(7,149)	(6,907)	(43,383)	(30,681)	(19,692)
Net loss	(12,032)	(11,644)	(10,995)	(10,619)	(9,076)	(8,091)	(7,303)	(6,920)	(45,290)	(31,390)	(20,610)
Net loss applicable to common shareholders	$ (12,032)	$ (11,644)	$ (10,995)	$ (10,619)	$ (9,076)	$ (8,849)	$ (9,209)	$ (8,826)	$ (45,290)	$ (35,960)	$ (27,518)
Per share data:
Net loss per common share - basic and diluted (in dollars per share)	$ (0.56)	$ (0.57)	$ (0.54)	$ (0.53)	$ (0.45)	$ (0.71)	$ (6.35)	$ (6.25)	$ (2.21)	$ (4.15)	$ (19.72)