Cerus (CERS) 10-K 8 Mar 17 2016 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Feb. 24, 2017	Jun. 30, 2016
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	FY
Trading Symbol	CERS
Entity Registrant Name	CERUS CORP
Entity Central Index Key	1,020,214
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Accelerated Filer
Entity Common Stock, Shares Outstanding		103,474,675
Entity Public Float			$ 543

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 22,560	$ 71,018
Short-term investments	45,116	25,698
Investment in marketable equity securities	3,952	11,163
Accounts receivable	6,868	5,794
Inventories	12,531	10,812
Prepaid expenses	1,274	1,166
Other current assets	1,804	4,755
Total current assets	94,105	130,406
Non-current assets:
Property and equipment, net	2,985	3,549
Goodwill	1,316	1,316
Intangible assets, net	738	940
Restricted cash	184	612
Other assets	4,148	2,579
Total assets	103,476	139,402
Current liabilities:
Accounts payable	8,587	5,217
Accrued liabilities	11,218	9,853
Manufacturing and development obligations - current		3,282
Debt - current	6,934	2,956
Deferred product revenue - current	149	554
Total current liabilities	26,888	21,862
Non-current liabilities:
Debt - non-current	12,441	16,848
Deferred income taxes	150	122
Manufacturing and development obligations - non-current	4,770	4,542
Other non-current liabilities	1,440	1,263
Total liabilities	45,689	44,637
Commitments and contingencies
Stockholders' equity:
Preferred stock, $0.001 par value; 5,000 shares authorized, issuable in series; zero shares issued and outstanding at December 31, 2016 and 2015, respectively
Common stock, $0.001 par value; 225,000 shares authorized; 103,475 and 99,095 shares issued and outstanding at December 31, 2016 and 2015, respectively	103	99
Additional paid-in capital	718,299	685,189
Accumulated other comprehensive income	103	7,289
Accumulated deficit	(660,718)	(597,812)
Total stockholders' equity	57,787	94,765
Total liabilities and stockholders' equity	$ 103,476	$ 139,402

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2016	Dec. 31, 2015
Statement Of Financial Position [Abstract]
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	225,000,000	225,000,000
Common stock, shares issued	103,475,000	103,475,000
Common stock, shares outstanding	99,095,000	99,095,000

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Statement [Abstract]
Product revenue	$ 37,183,000	$ 34,223,000	$ 36,416,000
Cost of product revenue	20,295,000	23,464,000	21,188,000
Gross profit on product revenue	16,888,000	10,759,000	15,228,000
Government contracts revenue	2,092,000
Operating expenses:
Research and development	31,322,000	25,643,000	21,800,000
Selling, general and administrative	48,753,000	45,989,000	37,729,000
Amortization of intangible assets	202,000	202,000	202,000
Impairment of long-lived assets	150,000	0	0
Total operating expenses	80,427,000	71,834,000	59,731,000
Loss from operations	(61,447,000)	(61,075,000)	(44,503,000)
Non-operating (expense) income, net:
Gain from revaluation of warrant liability		3,566,000	7,708,000
Foreign exchange gain (loss)	21,000	(396,000)	(1,296,000)
Interest expense	(2,445,000)	(1,705,000)	(599,000)
Other income, net	1,140,000	71,000	130,000
Total non-operating (expense) income, net	(1,284,000)	1,536,000	5,943,000
Loss before income taxes	(62,731,000)	(59,539,000)	(38,560,000)
Provision (benefit) for income taxes	175,000	(3,671,000)	195,000
Net loss	$ (62,906,000)	$ (55,868,000)	$ (38,755,000)
Net loss per share:
Basic	$ (0.62)	$ (0.58)	$ (0.52)
Diluted	$ (0.62)	$ (0.61)	$ (0.61)
Weighted average shares outstanding used for calculating net loss per share:
Basic	101,826	96,068	74,767
Diluted	101,826	96,905	76,534

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (62,906)	$ (55,868)	$ (38,755)
Other comprehensive (loss) income:
Unrealized (losses) gains on available-for-sale investments, net of taxes of zero, $3,825 and zero for 2016, 2015, and 2014, respectively	(7,186)	7,320	(38)
Comprehensive loss	$ (70,092)	$ (48,548)	$ (38,793)

CONSOLIDATED STATEMENTS OF COM6

CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement Of Income And Comprehensive Income [Abstract]
Unrealized (losses) gains on available-for-sale investments, taxes	$ 0	$ 3,825	$ 0

CONSOLIDATED STATEMENTS OF STOC

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Balance (in shares) at Dec. 31, 2013		71,859
Balance at Dec. 31, 2013	$ 42,795	$ 72	$ 545,905	$ 7	$ (503,189)
Net loss	(38,755)				(38,755)
Other comprehensive income (loss)	(38)			(38)
Issuance of common stock from public offering, net of offering costs (in shares)		4,341
Issuance of common stock from public offering, net of offering costs	18,521	$ 4	18,517
Issuance of common stock from exercise of stock options and/or warrants, and purchases from ESPP(In Shares)		4,204
Issuance of common stock from exercise of stock options and warrants, and purchases from ESPP	13,845	$ 4	13,841
Stock-based compensation	5,153		5,153
Balance (in shares) at Dec. 31, 2014		80,404
Balance at Dec. 31, 2014	41,521	$ 80	583,416	(31)	(541,944)
Net loss	(55,868)				(55,868)
Other comprehensive income (loss)	7,320			7,320
Issuance of common stock from public offering, net of offering costs (in shares)		14,636
Issuance of common stock from public offering, net of offering costs	75,376	$ 15	75,361
Issuance of common stock from exercise of stock options and/or warrants, and purchases from ESPP(In Shares)		4,055
Issuance of common stock from exercise of stock options and warrants, and purchases from ESPP	19,686	$ 4	19,682
Stock-based compensation	6,730		6,730
Balance (in shares) at Dec. 31, 2015		99,095
Balance at Dec. 31, 2015	94,765	$ 99	685,189	7,289	(597,812)
Net loss	(62,906)				(62,906)
Other comprehensive income (loss)	(7,186)			(7,186)
Issuance of common stock from public offering, net of offering costs (in shares)		3,526
Issuance of common stock from public offering, net of offering costs	21,981	$ 3	21,978
Issuance of common stock from exercise of stock options and/or warrants, and purchases from ESPP(In Shares)		854
Issuance of common stock from exercise of stock options and warrants, and purchases from ESPP	3,068	$ 1	3,067
Stock-based compensation	8,065		8,065
Balance (in shares) at Dec. 31, 2016		103,475
Balance at Dec. 31, 2016	$ 57,787	$ 103	$ 718,299	$ 103	$ (660,718)

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating activities
Net loss	$ (62,906,000)	$ (55,868,000)	$ (38,755,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	1,817,000	1,699,000	1,415,000
Stock-based compensation	8,065,000	6,730,000	5,153,000
Changes in valuation of warrant liability		(3,566,000)	(7,708,000)
Non-cash interest expense	1,017,000	508,000	131,000
Non-cash deferred manufacturing and development expense		434,000
Deferred income taxes	28,000	7,000	26,000
Loss on disposal of fixed assets			3,000
Impairment of long-lived assets	150,000	0	0
Non-cash tax benefit from other unrealized gain on available-for-sale securities		(3,825,000)
Gain on sale of investment in marketable equity securities	(750,000)
Changes in operating assets and liabilities:
Accounts receivable	(1,074,000)	(301,000)	632,000
Inventories	(1,781,000)	3,991,000	3,033,000
Other assets	1,327,000	1,379,000	(1,655,000)
Accounts payable	3,261,000	(3,866,000)	(973,000)
Accrued liabilities	1,330,000	1,359,000	(1,382,000)
Manufacturing and development obligations	(3,568,000)
Deferred product revenue	(445,000)	190,000	269,000
Net cash used in operating activities	(53,529,000)	(51,129,000)	(39,811,000)
Investing activities
Capital expenditures	(563,000)	(722,000)	(2,106,000)
Proceeds from sale of fixed assets			25,000
Purchases of investments	(82,811,000)	(90,407,000)	(25,981,000)
Proceeds from maturities and sale of investments	63,450,000	92,645,000	24,915,000
Net cash (used in) provided by investing activities	(19,924,000)	1,516,000	(3,147,000)
Financing activities
Net proceeds from equity incentives and warrants	3,068,000	12,767,000	11,592,000
Net proceeds from public offering	22,121,000	75,300,000	18,488,000
Proceeds from loans		10,000,000	9,848,000
Repayment of debt	(622,000)	(113,000)	(3,474,000)
Net cash provided by financing activities	24,567,000	97,954,000	36,454,000
Net (decrease) increase in cash, cash equivalents and restricted cash	(48,886,000)	48,341,000	(6,504,000)
Cash, cash equivalents and restricted cash, beginning of year	71,630,000	23,289,000	29,793,000
Cash, cash equivalents and restricted cash, end of year	22,744,000	71,630,000	23,289,000
Supplemental disclosures:
Cash paid for interest	1,366,000	1,087,000	563,000
Cash paid for income taxes	$ 157,000	153,000	$ 177,000
Unpaid manufacturing and development obligation		$ 7,051,000

Nature of Operations and Basis

Nature of Operations and Basis of Presentation	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Nature of Operations and Basis of Presentation	Note 1. Nature of Operations and Basis of Presentation Cerus Corporation (the “Company”) was incorporated in September 1991 and is developing and commercializing the INTERCEPT Blood System, which is designed to enhance the safety of blood components through pathogen reduction. The Company has worldwide commercialization rights for the INTERCEPT Blood System for platelets, plasma and red blood cells. The Company sells its INTERCEPT platelet and plasma systems in the United States of America (“U.S.”), Europe, the Commonwealth of Independent States (“CIS”) countries, the Middle East and selected countries in other regions around the world. The Company conducts significant research, development, testing and regulatory compliance activities on its product candidates that, together with anticipated selling, general, and administrative expenses, are expected to result in substantial additional losses, and the Company may need to adjust its operating plans and programs based on the availability of cash resources. The Company’s ability to achieve a profitable level of operations will depend on successfully completing development, obtaining additional regulatory approvals and achieving widespread market acceptance of its products. There can be no assurance that the Company will ever achieve a profitable level of operations.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Note 2. Summary of Significant Accounting Policies Principles of Consolidation The accompanying consolidated financial statements include those of Cerus Corporation and its subsidiary, Cerus Europe B.V. (together with Cerus Corporation, hereinafter “Cerus” or the “Company”) after elimination of all intercompany accounts and transactions. These consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the U.S. (“GAAP”) and pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). Use of Estimates The preparation of financial statements requires management to make estimates, assumptions and judgments that affect the reported amounts of assets, liabilities, revenue and expenses, and related disclosures of contingent assets and liabilities. On an ongoing basis, management evaluates its estimates, including those related to the accounts receivable, inventory reserves, fair values of investments, stock-based compensation, intangible assets and goodwill, useful lives of intangible assets and property and equipment, income taxes, and accrued liabilities, among others. We base our estimates on historical experience, future projections, and on various other assumptions that are believed to be reasonable under the circumstances. Actual results may differ from those estimates under different assumptions or conditions. Revenue The Company recognizes revenue in accordance with Accounting Standards Codification (“ASC”) Topic 605-25, “Revenue Recognition – Arrangements with Multiple Deliverables,” Revenue related to product sales is generally recognized when the Company fulfills its obligations for each element of an agreement. For all sales of the Company’s INTERCEPT Blood System products, the Company uses a binding purchase order or signed sales contract as evidence of an arrangement. The Company sells its platelet and plasma systems directly to blood banks, hospitals, universities, government agencies, as well as to distributors in certain regions. Generally, the Company’s contracts with its customers do not provide for open return rights, except within a reasonable time after receipt of goods in the case of defective or non-conforming product. Deliverables and the units of accounting vary according to the provisions of each purchase order or sales contract. For revenue arrangements with multiple elements, the Company determines whether the delivered elements meet the criteria as separate units of accounting. Such criteria require that the deliverable have stand-alone value to the customer and that if a general right of return exists relative to the delivered item, delivery or performance of the undelivered item(s) is considered probable and substantially in the control of the Company. Once the Company determines if the deliverable meets the criteria for a separate unit of accounting, the Company must determine how the consideration should be allocated between the deliverables and how the separate units of accounting should be recognized as revenue. Consideration received is allocated to elements that are identified as discrete units of accounting. Because the Company has no vendor specific objective evidence or third party evidence for its systems due to the Company’s variability in its pricing across the regions into which it sells its products, the allocation of revenue is based on best estimated selling price for the products sold. The objective of best estimated selling price is to determine the price at which the Company would transact a sale, had the product been sold on a stand-alone basis. The Company determines best estimated selling price for its systems by considering multiple factors. The Company regularly reviews best estimated selling price. At December 31, 2016 and 2015, the Company had $0.1 million and $0.6 million, respectively, of short-term deferred revenue on its consolidated balance sheets related to future performance obligations. At each of December 31, 2016 and 2015, the Company had $0.1 million of long-term deferred revenue included in “Other non-current liabilities” on it consolidated balance sheets related to future performance obligations. Freight costs charged to customers are recorded as a component of revenue. Taxes that the Company invoices to its customers and remits to governments are recorded on a net basis, which excludes such tax from product revenue. The Company receives reimbursement under its U.S. government contract that supports research and development of defined projects. The contract generally provides for reimbursement of approved costs incurred under the terms of the applicable contract. Revenue related to the cost reimbursement provisions under U.S. government contract are recognized as the qualified direct and indirect costs on the projects are incurred. The Company invoices under its U.S. government contract using the provisional rates in the government contract and thus is subject to future audits at the discretion of government. These audits could result in an adjustment to revenue previously reported, which adjustments potentially could be significant. The Company believes that revenue for periods not yet audited has been recorded in amounts that are expected to be realized upon final audit and settlement. Costs incurred related to services performed under the contract are included as a component of research and development or selling, general and administrative expenses in the Company’s consolidated statements of operations. The Company’s use of estimates in recording accrued liabilities for government contract activities (see “Use of Estimates” above) affects the revenue recorded from development funding and government contract. Research and Development Expenses In accordance with ASC Topic 730, “Accounting for Research and Development Expenses,” The Company’s use of estimates in recording accrued liabilities for R&D activities (see “Use of Estimates” above) affects the amounts of R&D expenses recorded from development funding and government contract. Actual results may differ from those estimates under different assumptions or conditions. Cash Equivalents The Company considers all highly liquid investments with original maturities of three months or less from the date of purchase to be classified as cash equivalents. These investments primarily consist of money market instruments, and are classified as available-for-sale. Investments Investments with original maturities of greater than three months primarily include corporate debt and U.S. government agency securities, and marketable equity securities of Aduro Biotech, Inc. (“Aduro”) are designated as available-for-sale and classified as short-term investments or investment in marketable equity securities, in accordance with ASC Topic 320, “ Accounting for Certain Investments in Debt and Equity Securities The Company also reviews its available-for-sale securities on a regular basis to evaluate whether any security has experienced an other-than-temporary decline in fair value. Other-than-temporary declines in market value, if any, are recorded in “Other income, net” on the Company’s consolidated statements of operations. Restricted Cash Prior to December 31, 2016, the Company held a certificate of deposit with a domestic bank for any potential decommissioning resulting from the Company’s possession of radioactive material. The certificate of deposit was held to satisfy the financial surety requirements of the California Department of Health Services and was recorded in “Restricted cash” on the Company’s condensed consolidated balance sheets at December 31, 2015. As of December 31, 2016, the Company also had certain non-U.S. dollar denominated deposits recorded as “Restricted cash” in compliance with certain foreign contractual requirements. Concentration of Credit Risk Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash equivalents, available-for-sale securities and accounts receivable. Pursuant to the Company’s investment policy, substantially all of the Company’s cash, cash equivalents and available-for-sale securities are maintained at major financial institutions of high credit standing. The Company monitors the financial credit worthiness of the issuers of its investments and limits the concentration in individual securities and types of investments that exist within its investment portfolio. Generally, all of the Company’s investments carry high credit quality ratings, which is in accordance with its investment policy. At December 31, 2016, the fair value of the Company’s marketable equity securities of Aduro is subject to the underlying volatility of Aduro’s stock price. At December 31, 2016, the Company does not believe there is significant financial risk from non-performance by the issuers of the Company’s cash equivalents and short-term investments. Concentrations of credit risk with respect to trade receivables exist. On a regular basis, including at the time of sale, the Company performs credit evaluations of its significant customers that it expects to sell to on credit terms. Generally, the Company does not require collateral from its customers to secure accounts receivable. To the extent that the Company determines specific invoices or customer accounts may be uncollectible, the Company establishes an allowance for doubtful accounts against the accounts receivable on its consolidated balance sheets and records a charge on its consolidated statements of operations as a component of selling, general and administrative expenses. The Company had three customers that accounted for more than 10% of the Company’s outstanding trade receivables at both December 31, 2016 and 2015. These customers cumulatively represented approximately 46% and 49% of the Company’s outstanding trade receivables at December 31, 2016 and 2015, respectively. To date, the Company has not experienced collection difficulties from these customers. Inventories At December 31, 2016 and 2015, inventory consisted of work-in-process and finished goods only. Finished goods include INTERCEPT disposable kits, illuminators, and certain replacement parts for the illuminators. Platelet and plasma systems’ disposable kits generally have a two-year life from the date of manufacture. Illuminators and replacement parts do not have regulated expiration dates. Work-in-process includes certain components that are manufactured over a protracted length of time before being sold to, and ultimately incorporated and assembled by Fresenius Kabi Deutschland GmbH or Fresenius, Inc. (with their affiliates, “Fresenius”) into the finished INTERCEPT disposable kits. The Company maintains an inventory balance based on its current sales projections, and at each reporting period, the Company evaluates whether its work-in-process inventory would be sold to Fresenius for production of finished units in order to sell to existing and prospective customers within the next twelve-month period. It is not customary for the Company’s production cycle for inventory to exceed twelve months. Instead, the Company uses its best judgment to factor in lead times for the production of its work-in-process and finished units to meet the Company’s forecasted demands. If actual results differ from those estimates, work-in-process inventory could potentially accumulate for periods exceeding one year. At December 31, 2016 and 2015, the Company classified its work-in-process inventory as a current asset on its consolidated balance sheets based on its evaluation that the work-in-process inventory would be sold to Fresenius for finished disposable kit production within each respective subsequent twelve-month period. Inventory is recorded at the lower of cost, determined on a first-in, first-out basis, or net realizable value. The Company uses significant judgment to analyze and determine if the composition of its inventory is obsolete, slow-moving or unsalable and frequently reviews such determinations. The Company writes down specifically identified unusable, obsolete, slow-moving, or known unsalable inventory that has no alternative use in the period that it is first recognized by using a number of factors including product expiration dates, open and unfulfilled orders, and sales forecasts. Any write-down of its inventory to net realizable value establishes a new cost basis and will be maintained even if certain circumstances suggest that the inventory is recoverable in subsequent periods. Costs associated with the write-down of inventory are recorded in “Cost of product revenue” on the Company’s consolidated statements of operations. At December 31, 2016, and 2015, the Company had $0.2 million and $1.8 million, respectively, recorded for potential obsolete, expiring or unsalable product. Property and Equipment, net Property and equipment is comprised of furniture, equipment, leasehold improvements, construction-in-progress, information technology hardware and software and is recorded at cost. At the time the property and equipment is ready for its intended use, it is depreciated on a straight-line basis over the estimated useful lives of the assets (generally three to five years). Leasehold improvements are amortized on a straight-line basis over the shorter of the lease term or the estimated useful lives of the improvements. Capitalization of Software Costs The Company capitalizes certain significant costs incurred in the acquisition and development of software for internal use, including the costs of the software, materials, and consultants during the application development stage. Costs incurred prior to the application development stage, costs incurred once the application is substantially complete and ready for its intended use, and other costs not qualifying for capitalization, including training and maintenance costs, are charged to expense as incurred. Goodwill and Intangible Assets, net Intangible assets, net, which include a license for the right to commercialize the INTERCEPT Blood System in Asia, are subject to ratable amortization over the original estimated useful life of ten years. The amortization of the Company’s intangible assets, net, is recorded in “Amortization of intangible assets” on the Company’s consolidated statements of operations. Goodwill is not amortized but instead is subject to an impairment test performed on an annual basis, or more frequently if events or changes in circumstances indicate that goodwill may be impaired. Such impairment analysis is performed on August 31 of each fiscal year, or more frequently if indicators of impairment exist. The test for goodwill impairment may be assessed using qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than the carrying amount. If the Company determines that it is more likely than not that the fair value of a reporting unit is less than the carrying amount, the Company must then proceed with performing the quantitative two-step process to test goodwill for impairment; otherwise, goodwill is not considered impaired and no further testing is warranted. The Company may choose not to perform the qualitative assessment to test goodwill for impairment and proceed directly to the quantitative two-step process; however, the Company may revert to the qualitative assessment to test goodwill for impairment in any subsequent period. The first step of the two-step process compares the fair value of each reporting unit with its respective carrying amount, including goodwill. The Company has determined that it operates in one reporting unit and estimates the fair value of its one reporting unit using the enterprise approach under which it considers the quoted market capitalization of the Company as reported on the Nasdaq Global Market. The Company considers quoted market prices that are available in active markets to be the best evidence of fair value. The Company also considers other factors, which include future forecasted results, the economic environment and overall market conditions. If the fair value of the reporting unit exceeds its carrying amount, goodwill of the reporting unit is not considered impaired and, therefore, the second step of the impairment test is unnecessary. The second step of the two-step process, which is used to measure the amount of impairment loss, compares the implied fair value of each reporting unit’s goodwill, based on the present value of future cash flows, with the respective carrying amount of that goodwill. If the carrying amount of the reporting unit’s goodwill exceeds the implied fair value of that goodwill, an impairment loss is recognized in an amount equal to that excess. The Company performs an impairment test on its intangible assets, in accordance ASC Topic 360-10, “Property, Plant and Equipment,” Long-lived Assets The Company evaluates its long-lived assets for impairment by continually monitoring events and changes in circumstances that could indicate carrying amounts of its long-lived assets may not be recoverable. When such events or changes in circumstances occur, the Company assesses recoverability by determining whether the carrying value of such assets will be recovered through the undiscounted expected future cash flows. If the expected undiscounted future cash flows are less than the carrying amount of these assets, the Company then measures the amount of the impairment loss based on the excess of the carrying amount over the fair value of the assets. Foreign Currency Remeasurement The functional currency of the Company’s foreign subsidiary is the U.S. dollar. Monetary assets and liabilities denominated in foreign currencies are remeasured in U.S. dollars using the exchange rates at the balance sheet date. Non-monetary assets and liabilities denominated in foreign currencies are remeasured in U.S. dollars using historical exchange rates. Revenues and expenses are remeasured using average exchange rates prevailing during the period. Remeasurements are recorded in the Company’s consolidated statements of operations. Stock-Based Compensation The Company accounts for stock-based compensation in accordance with ASC Topic 718, Compensation - Stock Compensation. For stock-based awards issued to non-employees, the Company follows ASC Topic 505-50, Equity Based Payment to Non-Employees See Note 13 for further information regarding the Company’s stock-based compensation assumptions and expenses. Income Taxes The Company accounts for income taxes using an asset and liability approach in accordance with ASC Topic 740, Accounting for Income Taxes Net Loss Per Share Basic net loss per share is computed by dividing net loss by the weighted average number of common shares outstanding for the period. Diluted net loss per share gives effect to all potentially dilutive common shares outstanding for the period. The potentially dilutive securities include stock options, employee stock purchase plan rights, warrants and restricted stock units, which are calculated using the treasury stock method. Diluted net loss per share also gives effect to potential adjustments to the numerator for gains resulting from the revaluation of warrants to fair value for the period, even if the Company is in a net loss position if the effect would result in more dilution. Certain potential dilutive securities were excluded from the dilution calculation for the years ended December 31, 2016, 2015 and 2014, as their inclusion would have been anti-dilutive. The following table sets forth the reconciliation of the numerator and denominator used in the computation of basic and diluted net loss per share for the years ended December 31, 2016, 2015 and 2014 (in thousands, except per share amounts): Year Ended December 31, 2016 2015 2014 Numerator for Basic and Diluted: Net loss used for basic calculation $ (62,906 ) $ (55,868 ) $ (38,755 ) Effect of revaluation of warrant liability — (3,566 ) (7,708 ) Adjusted net loss used for dilution calculation $ (62,906 ) $ (59,434 ) $ (46,463 ) Denominator: Basic weighted average number of shares outstanding 101,826 96,068 74,767 Effect of dilutive potential shares — 837 1,767 Diluted weighted average number of shares outstanding 101,826 96,905 76,534 Net loss per share: Basic $ (0.62 ) $ (0.58 ) $ (0.52 ) Diluted (0.62 ) (0.61 ) (0.61 ) The table below presents shares underlying stock options and restricted stock units that were excluded from the calculation of the weighted average number of shares outstanding used for the calculation of diluted net loss per share. These are excluded from the calculation due to their anti-dilutive effect for the years ended December 31, 2016, 2015 and 2014 (shares in thousands): Year Ended December 31, 2016 2015 2014 Weighted average number of anti-dilutive potential shares: Stock options 15,592 13,681 11,722 Restricted stock units 576 — — Total 16,168 13,681 11,722 Guarantee and Indemnification Arrangements The Company recognizes the fair value for guarantee and indemnification arrangements issued or modified by the Company. In addition, the Company monitors the conditions that are subject to the guarantees and indemnifications in order to identify if a loss has occurred. If the Company determines it is probable that a loss has occurred, then any such estimable loss would be recognized under those guarantees and indemnifications. Some of the agreements that the Company is a party to contain provisions that indemnify the counter party from damages and costs resulting from claims that the Company’s technology infringes the intellectual property rights of a third party or claims that the sale or use of the Company’s products have caused personal injury or other damage or loss. The Company has not received any such requests for indemnification under these provisions and has not been required to make material payments pursuant to these provisions. The Company generally provides for a one-year warranty on certain of its INTERCEPT blood-safety products covering defects in materials and workmanship. The Company accrues costs associated with warranty obligations when claims become known and are estimable. The Company has not experienced significant or systemic warranty claims nor is it aware of any existing current warranty claims. Accordingly, the Company had not accrued for any future warranty costs for its products at December 31, 2016 and 2015. Fair Value of Financial Instruments The Company applies the provisions of fair value relating to its financial assets and liabilities. The carrying amounts of accounts receivables, accounts payable, and other accrued liabilities approximate their fair value due to the relative short-term maturities. Based on the borrowing rates currently available to the Company for loans with similar terms, the Company believes the fair value of its debt approximates their carrying amounts. The Company measures and records certain financial assets and liabilities at fair value on a recurring basis, including its available-for-sale securities and warrant liability prior to the expiration and exercise of the warrants in November 2015. The Company classifies instruments within Level 1 if quoted prices are available in active markets for identical assets, which include the Company’s cash accounts and money market funds. The Company classifies instruments in Level 2 if the instruments are valued using observable inputs to quoted market prices, benchmark yields, reported trades, broker/dealer quotes or alternative pricing sources with reasonable levels of price transparency. These instruments include the Company’s corporate debt and U.S. government agency securities holdings. The available-for-sale securities are held by a custodian who obtains investment prices from a third party pricing provider that uses standard inputs (observable in the market) to models which vary by asset class. The Company classifies instruments in Level 3 if one or more significant inputs or significant value drivers are unobservable. The Company assesses any transfers among fair value measurement levels at the end of each reporting period. See Notes 3 for further information regarding the Company’s valuation of financial instruments. New Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (“FASB”) issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606), Revenue from Contracts with Customers (Topic 606), Deferral of the Effective Date Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations (Reporting Revenue Gross versus Net) Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing, Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients, Technical Corrections and Improvements to Topic 606, Revenue from Contracts with Customers In August 2014, the FASB issued ASU No. 2014-15, Presentation of Financial Statements—Going Concern In April 2015, the FASB issued ASU No. 2015-03, Interest—Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs In January 2016, the FASB issued ASU No. 2016-01, Financial Instruments-Overall (Subtopic 825-10) In February 2016, the FASB issued ASU No. 2016-02, Leases In March 2016, the FASB issued ASU No. 2016-09, Compensation-Stock Compensation (Topic 718):Improvements to Employee Share-Based Payment Accounting, In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash, a consensus of the FASB Emerging Issues Task Force, In January 2017, the FASB issued ASU No. 2017-04, Intangibles—Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment,

Fair Value on Financial Instrum

Fair Value on Financial Instruments	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Fair Value on Financial Instruments	Note 3. Fair Value on Financial Instruments The Company uses certain assumptions that market participants would use to determine the fair value of an asset or liability in pricing the asset or liability in an orderly transaction between market participants at the measurement date. The identification of market participant assumptions provides a basis for determining what inputs are to be used for pricing each asset or liability. A fair value hierarchy has been established which gives precedence to fair value measurements calculated using observable inputs over those using unobservable inputs. This hierarchy prioritized the inputs into three broad levels as follows: • Level 1: Quoted prices in active markets for identical instruments • Level 2: Other significant observable inputs (including quoted prices in active markets for similar instruments) • Level 3: Significant unobservable inputs (including assumptions in determining the fair value of certain investments) Money market funds are highly liquid investments and are actively traded. The pricing information on these investment instruments are readily available and can be independently validated as of the measurement date. This approach results in the classification of these securities as Level 1 of the fair value hierarchy. To estimate the fair value of Level 2 debt securities as of December 31, 2016, the Company’s primary service relies on inputs from multiple industry-recognized pricing sources to determine the price for each investment. Corporate debt and U.S. government agency securities are systematically priced by this service as of the close of business each business day. If the primary pricing service does not price a specific asset a secondary pricing service is utilized. The fair values of the Company’s financial assets and liabilities were determined using the following inputs at December 31, 2016 (in thousands): Balance sheet Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs classification Total (Level 1) (Level 2) (Level 3) Money market funds Cash and cash equivalents $ 8,991 $ 8,991 $ — $ — United States government agency securities Short-term investments 8,029 — 8,029 — Corporate debt securities Short-term investments 37,087 — 37,087 — Marketable equity securities Marketable equity securities 3,952 3,952 — — Total financial assets $ 58,059 $ 12,943 $ 45,116 $ — The fair values of the Company’s financial assets and liabilities were determined using the following inputs at December 31, 2015 (in thousands): Balance sheet Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs classification Total (Level 1) (Level 2) (Level 3) Money market funds Cash and cash equivalents $ 59,302 $ 59,302 $ — $ — Corporate debt securities Short-term investments 25,698 — 25,698 — Marketable equity securities Marketable equity securities 11,163 11,163 — — Total financial assets $ 96,163 $ 70,465 $ 25,698 $ — A reconciliation of the beginning and ending balances for the warrant liability using significant unobservable inputs (Level 3) from December 31, 2014 to December 31, 2015, was as follows (in thousands): Balance at December 31, 2014 $ 10,485 Decrease in fair value of warrants (3,566 ) Settlement of warrants exercised (6,919 ) Balance at December 31, 2015 $ — The Company did not have any outstanding warrants during 2016. See Notes 2 and 12 for further information regarding the Company’s valuation techniques and unobservable inputs for the warrant liability using significant unobservable inputs (Level 3).The Company did not have any transfers among fair value measurement levels during the years ended December 31, 2016 and 2015.

Available-for-sale Securities

Available-for-sale Securities	12 Months Ended
	Dec. 31, 2016
Investments Debt And Equity Securities [Abstract]
Available-for-sale Securities	Note 4. Available-for-sale Securities The following is a summary of available-for-sale securities at December 31, 2016 (in thousands): December 31, 2016 Amortized Cost Gross Unrealized Gain Gross Unrealized Loss Fair Value Money market funds $ 8,991 $ — $ — $ 8,991 United States government agency securities 8,030 — (1 ) 8,029 Corporate debt securities 37,110 — (23 ) 37,087 Marketable equity securities — 3,952 — 3,952 Total available-for-sale securities $ 54,131 $ 3,952 $ (24 ) $ 58,059 The following is a summary of available-for-sale securities at December 31, 2015(in thousands): December 31, 2015 Amortized Cost Gross Unrealized Gain Gross Unrealized Loss Fair Value Money market funds $ 59,302 $ — $ — $ 59,302 Corporate debt securities 25,747 — (49 ) 25,698 Marketable equity securities — 11,163 — 11,163 Total available-for-sale securities $ 85,049 $ 11,163 $ (49 ) $ 96,163 Available-for-sale securities at December 31, 2016 and 2015, consisted of the following by contractual maturity (in thousands): December 31, 2016 December 31, 2015 Amortized Cost Fair Value Amortized Cost Fair Value One year or less $ 54,131 $ 54,107 $ 85,049 $ 85,000 Marketable equity securities — 3,952 — 11,163 Greater than one year and less than five years — — — — Total available-for-sale securities $ 54,131 $ 58,059 $ 85,049 $ 96,163 The following tables show all available-for-sale marketable securities in an unrealized loss position for which an other-than-temporary impairment has not been recognized and the related gross unrealized losses and fair value, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position (in thousands): December 31, 2016 Less than 12 Months 12 Months or Greater Total Fair Value Unrealized Loss Fair Value Unrealized Loss Fair Value Unrealized Loss Money market funds $ — $ — $ — $ — $ — $ — United States government agency securities 6,035 (1 ) — — 6,035 (1 ) Corporate debt securities 34,086 (23 ) — — 34,086 (23 ) Total available-for-sale securities $ 40,121 $ (24 ) $ — $ — $ 40,121 $ (24 ) December 31, 2015 Less than 12 Months 12 Months or Greater Total Fair Value Unrealized Loss Fair Value Unrealized Loss Fair Value Unrealized Loss Money market funds $ — $ — $ — $ — $ — $ — United States government agency securities — — — — — — Corporate debt securities 20,170 (46 ) 5,528 (3 ) 25,698 (49 ) Total available-for-sale securities $ 20,170 $ (46 ) $ 5,528 $ (3 ) $ 25,698 $ (49 ) As of December 31, 2016, the Company considered the declines in market value of its marketable securities investment portfolio to be temporary in nature and did not consider any of its investments other-than-temporarily impaired. The Company typically invests in highly-rated securities, and its investment policy limits the amount of credit exposure to any one issuer. The policy generally requires investments to be investment grade, with the primary objective of minimizing the potential risk of principal loss. Fair values were determined for each individual security in the investment portfolio. When evaluating an investment for other-than-temporary impairment, the Company reviews factors such as the length of time and extent to which fair value has been below its cost basis, the financial condition of the issuer and any changes thereto, changes in market interest rates, and the Company’s intent to sell, or whether it is more likely than not it will be required to sell, the investment before recovery of the investment’s cost basis. During the years ended December 31, 2016, 2015 and 2014, the Company did not recognize any other-than-temporary impairment loss. The Company has no current requirement or intent to sell the securities in an unrealized loss position. The Company expects to recover up to (or beyond) the initial cost of investment for securities held. The Company recognized $0.8 million of realized gains from the sale of available-for-sale investments during the year ended December 31, 2016. Minimal gross realized gains were recorded during the years ended December 31, 2015 and 2014. The Company did not record any gross realized losses during the years ended December 31, 2016, 2015 and 2014.

Inventories

Inventories	12 Months Ended
	Dec. 31, 2016
Inventory Disclosure [Abstract]
Inventories	Note 5. Inventories Inventories at December 31, 2016 and 2015, consisted of the following (in thousands): December 31, 2016 2015 Work-in-process $ 5,044 $ 3,187 Finished goods 7,487 7,625 Total inventories $ 12,531 $ 10,812

Property and Equipment, net

Property and Equipment, net	12 Months Ended
	Dec. 31, 2016
Property Plant And Equipment [Abstract]
Property and Equipment, net	Note 6. Property and Equipment, net Property and equipment, net at December 31, 2016 and 2015, consisted of the following (in thousands): December 31, 2016 2015 Leasehold improvements $ 5,678 $ 5,678 Machinery and equipment 1,925 1,603 Demonstration equipment 167 145 Furniture and fixtures 871 794 Computer equipment 603 591 Computer software 2,908 2,935 Consigned equipment 1,058 1,010 Construction-in-progress 62 219 Total property and equipment, gross 13,272 12,975 Accumulated depreciation and amortization (10,287 ) (9,426 ) Total property and equipment, net $ 2,985 $ 3,549 Depreciation and amortization expense related to property and equipment, net was $1.1 million, $1.1 million and $0.7 million for the years ended December 31, 2016, 2015 and 2014, respectively. As part of the Company’s 2016 review of property and equipment, $0.2 million was recorded to impairment of long-lived assets on the consolidated statement of operations for construction-in-progress related to a deposit associated with a terminated agreement. No such impairment charges were incurred for the years ended December 31, 2015 and 2014.

Goodwill and Intangible Assets,

Goodwill and Intangible Assets, net	12 Months Ended
	Dec. 31, 2016
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets, net	Note 7. Goodwill and Intangible Assets, net Goodwill During the year ended December 31, 2016, the Company did not dispose of or recognize additional goodwill. On August 31, 2016, the Company performed its impairment test of goodwill. As described in Note 2 above, the Company applied the enterprise approach by reviewing the quoted market capitalization of the Company as reported on the Nasdaq Global Market to calculate the fair value. In addition, the Company considered its future forecasted results, the economic environment and overall market conditions. As a result of the Company’s assessment that its fair value of the reporting unit exceeded its carrying amount, the Company determined that goodwill was not impaired. Intangible Assets, net The following is a summary of intangible assets, net at December 31, 2016 (in thousands): December 31, 2016 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Acquisition-related intangible assets: Reacquired license - INTERCEPT Asia $ 2,017 $ (1,279 ) $ 738 Total intangible assets $ 2,017 $ (1,279 ) $ 738 The following is a summary of intangible assets, net at December 31, 2015 (in thousands): December 31, 2015 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Acquisition-related intangible assets: Reacquired license - INTERCEPT Asia $ 2,017 $ (1,077 ) $ 940 Total intangible assets $ 2,017 $ (1,077 ) $ 940 During the years ended December 31, 2016, 2015 and 2014, there were no impairment charges recognized related to the Company’s intangible assets. At December 31, 2016, the expected annual amortization expense of the intangible assets, net is $0.2 million beginning with the year ending December 31, 2017, and each subsequent year thereafter through the year ending December 31, 2019, and $0.1 million for the year ending December 31, 2020.

Marketable Equity Investments

Marketable Equity Investments	12 Months Ended
	Dec. 31, 2016
Investments All Other Investments [Abstract]
Marketable Equity Investments	Note 8. Marketable Equity Investments In connection with the agreements to license the immunotherapy technologies to Aduro in 2009, the Company received preferred shares of Aduro, a privately held company at the time the Company received such shares. Pursuant to these license agreements, the Company was eligible to receive a 1% royalty fee on any future sales resulting from the licensed technology. For the years ended December 31, 2016, 2015 and 2014, the Company has not received any royalty payments from Aduro pursuant to this agreement. The Company historically accounted for the investment under the cost method of accounting with a net carrying value of zero. In April 2015, Aduro’s common stock began trading on the NASDAQ Global Select Market, under the symbol “ADRO”. At the time of Aduro’s initial public offering (“IPO”), the Company’s preferred shares in Aduro converted to 396,700 shares of common stock, and the fair value of the Company’s investment became readily determinable and, as a result became a marketable equity security. Therefore, the Company no longer accounts for the investment in Aduro under the cost basis of accounting. The Company now reflects the investment in Aduro as an available-for-sale security included in investment in marketable equity securities on the Company’s consolidated balance sheet (Note 4) and will adjust the carrying value of this investment to fair value each quarterly reporting period, with changes in fair value recorded within other comprehensive income (loss), net of tax. During the year ended December 31, 2016, the Company sold 50,000 shares of Aduro common stock and recognized a gain of $0.8 million in “Other income, net” on the Company’s consolidated statements of operations. As of December 31, 2016, the Company had 346,700 shares of Aduro common stock.

Accrued Liabilities

Accrued Liabilities	12 Months Ended
	Dec. 31, 2016
Payables And Accruals [Abstract]
Accrued Liabilities	Note 9. Accrued Liabilities Accrued liabilities at December 31, 2016 and 2015, consisted of the following (in thousands): December 31, 2016 2015 Accrued compensation and related costs $ 7,098 $ 5,198 Accrued professional services 2,511 2,337 Accrued customer costs 534 987 Accrued insurance premiums 476 438 Other accrued expenses 599 893 Total accrued liabilities $ 11,218 $ 9,853

Debt

Debt	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Debt	Note 10. Debt Debt at December 31, 2016, consisted of the following (in thousands): December 31, 2016 Principal Unamortized Discount Net Carrying Value Loan and Security Agreement $ 19,499 $ (124 ) $ 19,375 Less: debt - current (7,013 ) 79 (6,934 ) Debt - non-current $ 12,486 $ (45 ) $ 12,441 Debt at December 31, 2015, consisted of the following (in thousands): December 31, 2015 Principal Unamortized Discount Total Loan and Security Agreement $ 20,000 $ (196 ) $ 19,804 Less: debt - current (3,050 ) 94 (2,956 ) Debt - non-current $ 16,950 $ (102 ) $ 16,848 Principal and interest payments on debt at December 31, 2016, are expected to be as follows: Year ended December 31, Principal Interest Total 2017 7,013 1,160 8,173 2018 8,178 613 8,791 2019 4,308 1,488 5,796 Total $ 19,499 $ 3,261 $ 22,760 Loan and Security Agreement On June 30, 2014, the Company entered into a five year loan and security agreement with Oxford Finance LLC (the “Term Loan Agreement”) to borrow up to $30.0 million in term loans in three equal tranches (the “Term Loans”). On June 30, 2014, the Company received $10.0 million from the first tranche (“Term Loan A”). The second tranche of $10.0 million (“Term Loan B”) was drawn on June 15, 2015. On September 29, 2015, the Term Loan Agreement was amended to extend (i) the period in which the third tranche of $10.0 million (“Term Loan C”) could have been drawn and (ii) the interest-only period for all advances under the Term Loan Agreement. As a result, the accounting treatment for the Term Loan continued under the interest method, with a new effective interest rate based on revised cash flows calculated on a prospective basis upon the execution of the amendment to the Term Loan Agreement. As amended, the availability of Term Loan C was subject to the Company achieving consolidated trailing six months’ revenue at a specified threshold (the “Revenue Event”) no later than June 30, 2016. The Company did not achieve the Revenue Event by June 30, 2016, and therefore Term Loan C was not available to be drawn. Term Loan A bears an interest rate of 6.95%. Term Loan B bears an interest rate of 7.01%. Term Loans A and B mature on June 1, 2019. The Company was required to make interest only payments through June 2016, followed by thirty-six months of equal principal and interest payments thereafter. On July 28, 2016, the Term Loan Agreement was amended to include an additional interest-only period for all advances under the Term Loan Agreement. As amended, the Company is required to make interest only payments from August 2016 through January 2017, followed by twenty-nine months of equal principal and interest payments thereafter. The Company determined that the amendment to the Term Loan Agreement resulted in a modification. As a result, the accounting treatment for the Term Loan will continue under the interest method, with a new effective interest rate based on revised cash flows calculated on a prospective basis upon the execution of the amendment to the Term Loan Agreement. The Company is also required to make a final payment equal to 7% of the principal amounts of the Term Loans drawn payable on the earlier to occur of maturity or prepayment. The costs associated with the final payment are recognized as interest expense over the life of the Term Loans. The Company may prepay at any time the Term Loans subject to declining prepayment fees over the term of the Term Loan Agreement. The Company pledged all current and future assets, excluding its intellectual property and 35% of the Company’s investment in its subsidiary, Cerus Europe B.V., as security for borrowings under the Term Loan Agreement. The Term Loan Agreement contains certain nonfinancial covenants, with which the Company was in compliance at December 31, 2016.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2016
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 11. Commitments and Contingencies Operating Leases The Company leases its office facilities, located in Concord, California and Amersfoort, the Netherlands, and certain equipment under non-cancelable operating leases with initial terms in excess of one year that require the Company to pay operating costs, property taxes, insurance and maintenance. The operating leases expire at various dates through 2021, with certain of the leases providing for renewal options, provisions for adjusting future lease payments based on the consumer price index, and the right to terminate the lease early. The Company’s leased facilities qualify as operating leases under ASC Topic 840, “Leases” Future minimum non-cancelable lease payments under operating leases as of December 31, 2016, are as follows (in thousands): Year ended December 31, 2017 $ 1,233 2018 868 2019 739 2020 30 2021 2 Total minimum non-cancellable lease payments $ 2,872 Rent expense for office facilities was $0.8 million, $0.8 million and $0.7 million for the years ended December 31, 2016, 2015 and 2014, respectively. Financed Leasehold Improvements In 2010, the Company financed $1.1 million of leasehold improvements. The Company pays for the financed leasehold improvements as a component of rent and is required to reimburse its landlord over the remaining life of the respective leases. At December 31, 2016, the Company had an outstanding liability of $0.4 million related to these leasehold improvements, of which $0.1 million was reflected in “Accrued liabilities” and $0.3 million was reflected in “Other non-current liabilities” on the Company’s consolidated balance sheets. Purchase Commitments The Company is party to agreements with certain providers for certain components of INTERCEPT Blood System which the Company purchases from third party manufacturers. Certain of these agreements require minimum purchase commitments from the Company. The Company has paid $6.9 million, $7.7 million and $6.8 million for goods under agreements which are subject to minimum purchase commitments during the years ended December 31, 2016, 2015 and 2014, respectively. As of December 31, 2016, the Company has future minimum purchase commitments under these agreements of approximately $6.5 million, $0.6 million, $0.3 million, $0.4 million and $1.7 million for the years ending December 31, 2017, 2018, 2019, 2020 and 2021 respectively. In June 2014, the Company terminated its distribution agreement with one of its distributors in certain countries and entered into an agreement to provide for specific post-termination obligations (the “Transition Agreement”). The Transition Agreement expired September 30, 2014. The Company is required to pay this former distributor a fee of €10 per disposable kit for platelet systems sold by the Company to any customer in certain countries commencing with the termination of the agreement through April 1, 2018, subject to a maximum payment of €3 million. During the year ended December 31, 2016, the Company paid approximately $0.5 million (€0.5 million) associated with this fee. To date, the Company has paid €0.9 million cumulatively of the €3 million maximum payment. As of December 31, 2016, the Company had accrued $0.1 million (€0.1 million) associated with this fee. As this former distributor remains as a customer in other countries, in accordance with ASC Topic 605-50 “Customer Payments and Incentives”

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2016
Equity [Abstract]
Stockholders' Equity	Note 12. Stockholders’ Equity Sales Agreement On May 5, 2016, the Company entered into Amendment No. 2 to the Controlled Equity Offering SM Stockholder Rights Plan In October 2009, the Company’s Board of Directors adopted an amendment to its 1999 stockholder rights plan, commonly referred to as a “poison pill,” to reduce the exercise price, extend the expiration date and revise certain definitions under the plan. The stockholder rights plan is intended to deter hostile or coercive attempts to acquire the Company. The stockholder rights plan enables stockholders to acquire shares of the Company’s common stock, or the common stock of an acquirer, at a substantial discount to the public market price should any person or group acquire more than 15% of the Company’s common stock without the approval of the Board of Directors under certain circumstances. The Company has designated 250,000 shares of Series C Junior Participating preferred stock for issuance in connection with the stockholder rights plan. As of December 31, 2016, no Series C Junior Participating preferred stock has been issued. Common Stock and Associated Warrant Liability In November 2010, the Company issued warrants (“2010 Warrants”) to purchase 3.7 million shares of common stock, exercisable at an exercise price of $3.20 per share. The 2010 Warrants became exercisable on May 15, 2011, and were exercisable for a period of five years from the issue date. In 2015, all outstanding 2010 Warrants were exercised in full. At December 31, 2016, the Company had no outstanding warrants remaining.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	Note 13. Stock-Based Compensation Employee Stock Plans Employee Stock Purchase Plan The Company maintains an Employee Stock Purchase Plan (the “Purchase Plan”), which is intended to qualify as an employee stock purchase plan within the meaning of Section 423(b) of the Internal Revenue Code. Under the Purchase Plan, the Company’s Board of Directors may authorize participation by eligible employees, including officers, in periodic offerings. Under the Purchase Plan eligible employee participants may purchase shares of common stock of the Company at a purchase price equal to 85% of the lower of the fair market value per share on the start date of the offering period or the fair market value per share on the purchase date. The Purchase Plan consists of a fixed offering period of 12 months with two purchase periods within each offering period. The Purchase Plan was authorized to issue an aggregate of 1,320,500 shares. On June 10, 2015, the Company’s stockholders approved an amendment and restatement of the Purchase Plan that increased the aggregate number of shares of common stock authorized for issuance under the Purchase Plan by 1,500,000 shares. At December 31, 2016, the Company had 1,438,211 shares available for future issuance. 2008 Equity Incentive Plan and Inducement Plan The Company also maintains an equity compensation plan to provide long-term incentives for employees, contractors, and members of its Board of Directors. The Company currently grants equity awards from one plan, the 2008 Equity Incentive Plan (the “2008 Plan”). The 2008 Plan allows for the issuance of non-statutory and incentive stock options, restricted stock, restricted stock units (“RSUs”), stock appreciation rights, other stock-related awards, and performance awards which may be settled in cash, stock, or other property. On June 6, 2012 and June 12, 2013, the stockholders approved amendments to the 2008 Plan (collectively the “Amended 2008 Plan”) such that the Amended 2008 Plan has reserved for issuance an amount not to exceed 19.5 million shares. On June 10, 2015, the Company’s stockholders approved an amendment and restatement of the 2008 Plan that increased the aggregate number of shares of common stock authorized for issuance under the 2008 Plan by 5,000,000 shares. Awards under the Amended 2008 Plan generally have a maximum term of 10 years from the date of the award. The Amended 2008 Plan generally requires options to be granted at 100% of the fair market value of the Company’s common stock subject to the option on the date of grant. Options granted by the Company to employees generally vest over four years. RSUs are measured based on the fair market value of the underlying stock on the date of grant and will generally vest over three years. Performance-based stock or cash awards granted under the Amended 2008 Plan are limited to either 500,000 shares of common stock or $1.0 million per recipient per calendar year. The attainment of any performance-based awards granted shall be conclusively determined by a committee designated by the Company’s Board of Directors. At December 31, 2016, no performance-based stock options were outstanding. On August 31, 2016, the Company’s Board of Directors adopted the Cerus Corporation Inducement Plan (the “Inducement Plan”), and reserved 1,250,000 shares of its common stock under the Inducement Plan to be used exclusively for the issuance of non-statutory stock options and restricted stock units to individuals who were not previously employees or directors of the Company, or who had experienced a bona fide period of non-employment, as an inducement material to the individual’s entry into employment with the Company within the meaning of Rule 5635(c)(4) of the NASDAQ Listing Rules. The Inducement Plan was approved by the Company’s Board of Directors without stockholder approval pursuant to Rule 5635(c)(4), and the terms and conditions of the Inducement Plan are substantially similar to the Amended 2008 Plan. At December 31, 2016, the Company had an aggregate of approximately 21.6 million shares of its common stock subject to outstanding options or remaining available for future issuance under the Amended 2008 Plan, of which approximately 15.8 million shares and 0.7 million shares were subject to outstanding options and outstanding RSUs, respectively, and approximately 5.1 million shares were available for future issuance under the Amended 2008 Plan. The Company’s policy is to issue new shares of common stock upon the exercise of options. Activity under the Company’s equity incentive plans related to stock options is set forth below (in thousands except weighted average exercise price): Number of Options Outstanding Weighted Average Exercise Price per Share Balances at December 31, 2015 14,119 $ 4.21 Granted 2,722 5.39 Forfeited (287 ) 4.93 Expired (128 ) 9.18 Exercised (639 ) 3.45 Balances at December 31, 2016 15,787 4.39 Activity under the Company’s equity incentive plans related to RSUs is set forth below (in thousands except per share amounts): Number of Shares Outstanding Weighted Average Grant Date Fair Value per Share Balances at December 31, 2015 — $ — Granted 762 5.26 Forfeited (23 ) 5.06 Vested — — Balances at December 31, 2016 739 5.26 Information regarding the Company’s stock options outstanding, stock options vested and expected to vest, and stock options exercisable at December 31, 2016, was as follows (in thousands except weighted average exercise price and contractual term): Number Weighted Exercise Weighted Average Remaining Contractual Term (Years) Aggregate Value Balances at December 31, 2016 Stock options outstanding 15,787 $ 4.39 6.3 $ 8,696 Stock options vested and expected to vest 15,541 4.38 6.2 8,695 Stock options exercisable 10,600 4.03 5.3 8,557 The aggregate intrinsic value in the table above is calculated as the difference between the exercise price of the stock option and the Company’s closing stock price on the last trading day of each respective fiscal period. The total intrinsic value of options exercised for the years ended December 31, 2016, 2015 and 2014, was $1.9 million, $1.2 million and $3.8 million, respectively. Stock-based Compensation Expense Stock-based compensation expense recognized on the Company’s consolidated statements of operations for the years ended December 31, 2016, 2015 and 2014, was as follows (in thousands): Year Ended December 31, 2016 2015 2014 Stock-based compensation expense by caption: Research and development $ 1,091 $ 1,260 $ 998 Selling, general and administrative 6,974 5,470 4,155 Total stock-based compensation expense $ 8,065 $ 6,730 $ 5,153 Stock-based compensation expense in the above table does not reflect any income taxes as the Company has experienced a history of net losses since its inception and has a full valuation allowance on its deferred tax assets. In addition, there was neither income tax benefits realized related to stock-based compensation expense nor any stock-based compensation costs capitalized as part of an asset during the years ended December 31, 2016, 2015 and 2014. The Company has also not recorded any stock-based compensation associated with performance-based stock options during the years ended December 31, 2016, 2015 and 2014. As of December 31, 2016, the Company expects to recognize the remaining unamortized stock-based compensation expense of $11.2 million and $2.6 million, respectively, related to non-vested stock options and RSUs, net of estimated forfeitures, over an estimated remaining weighted average period of 2.4 years and 2.2 years, respectively. Valuation Assumptions for Stock-based Compensation The Company currently uses the Black-Scholes option pricing model to determine the grant-date fair value of stock options and employee stock purchase plan shares. The Black-Scholes option-pricing model is affected by the Company’s stock price, as well as assumptions regarding a number of complex and subjective variables, which include the expected term of the grants, actual and projected employee stock option exercise behaviors, including forfeitures, the Company’s expected stock price volatility, the risk-free interest rate and expected dividends. The Company recognizes the grant-date fair value of the stock award as stock-based compensation expense on a straight-line basis over the requisite service period, which is the vesting period, and is adjusted for estimated forfeitures. The expected life of the stock options is based on observed historical exercise patterns. Groups of employees having similar historical exercise behavior are considered separately for valuation purposes. The Company estimates stock option forfeitures based on historical data for employee groups. The total number of stock options expected to vest is adjusted by actual and estimated forfeitures. The expected volatility is estimated by using historical volatility of the Company’s common stock. The risk-free interest rate is based on the implied yield on a U.S. Treasury zero-coupon issue with a remaining term commensurate with the expected term of the option. The Company does not anticipate paying any cash dividends in the foreseeable future and therefore uses an expected dividend yield of zero. The weighted average assumptions used to value the Company’s stock-based awards for the years ended December 31, 2016, 2015 and 2014, was as follows: Year Ended December 31, 2016 2015 2014 Stock Options: Expected term (in years) 5.85 5.66 5.71 Estimated volatility 49% 56% 61% Risk-free interest rate 1.41% 1.55% 1.73% Expected dividend yield 0% 0% 0% Employee Stock Purchase Plan Rights: Expected term (in years) 0.76 0.75 0.76 Estimated volatility 47% 53% 52% Risk-free interest rate 0.55% 0.28% 0.10% Expected dividend yield 0% 0% 0% The weighted average grant-date fair value of stock options granted during the years ended December 31, 2016, 2015 and 2014, was $2.55 per share, $2.35 per share and $3.28 per share, respectively. The weighted average grant-date fair value of employee stock purchase rights during the years ended December 31, 2016, 2015 and 2014, was $1.87 per share, $1.54 per share and $1.42 per share, respectively.

Retirement Plan

Retirement Plan	12 Months Ended
	Dec. 31, 2016
Compensation And Retirement Disclosure [Abstract]
Retirement Plan	Note 14. Retirement Plan The Company maintains a defined contribution savings plan (the “401(k) Plan”) that qualifies under the provisions of Section 401(k) of the Internal Revenue Code and covers eligible U.S. employees of the Company. Under the terms of the 401(k) Plan, eligible U.S. employees may make pre-tax dollar contributions of up to 60% of their eligible pay up to a maximum cap established by the IRS. The Company may contribute a discretionary percentage of qualified individual employee’s salaries, as defined, to the 401(k) Plan. The Company has not contributed to the 401(k) Plan during the years ended December 31, 2016, 2015 and 2014.

Development and License Agreeme

Development and License Agreements	12 Months Ended
	Dec. 31, 2016
Development And License Agreements [Abstract]
Development and License Agreements	Note 15. Development and License Agreements Agreements with Fresenius Fresenius manufactures and supplies the platelet and plasma systems to the Company under a supply agreement. Under the previous agreements with Fresenius, the Company was required to pay royalties to Fenwal Inc. (“Fenwal”), a subsidiary of Fresenius, on INTERCEPT Blood System product sales at royalty rates that varied by product. During the years ended December 31, 2016, 2015 and 2014, the Company made royalty payments to Fresenius of zero, $1.9 million and $2.5 million, respectively. In addition, Fresenius was obligated to sell, and the Company was obligated to purchase, up to a certain specified annual volume of finished disposable kits for the platelet and plasma systems from Fresenius for both clinical and commercial use. The pricing was fixed for finished kits with successive decreasing pricing tiers at various annual production volumes. Fresenius was also obligated to purchase and maintain specified inventory levels of the Company’s proprietary inactivation compounds and adsorption media from the Company at fixed prices. In October 2015, the Company entered into an Amended and Restated Manufacturing and Supply Agreement (the “2015 Agreement”) with Fresenius, which amended and restated its previous agreements. Under the 2015 Agreement, Fresenius continues to be obligated to sell and the Company is obligated to purchase finished disposable kits for the Company’s platelet and plasma systems and the Company’s red blood cell system product candidate (the “RBC Sets”). The 2015 Agreement permits the Company to purchase platelet and plasma systems and RBC Sets from third parties to the extent necessary to maintain supply qualifications with such third parties or where local or regional manufacturing is needed to obtain product registrations or sales. Pricing terms per unit are initially fixed and decline at specified annual production levels, and are subject to certain adjustments after the initial pricing term. Under the 2015 Agreement, the Company is no longer required to make royalty payments to Fenwal for the sale of products after June 30, 2015. Under the 2015 Agreement, the Company maintains the amounts due from the components sold to Fresenius as a current asset on its accompanying consolidated balance sheets until such time as the Company purchases finished disposable kits using those components. The 2015 Agreement also requires the Company to make certain payments totaling €8.6 million (“Manufacturing and Development Payments”) to Fresenius in 2016 and on December 31 of the earlier of (a) the year of achievement of certain production volumes or (b) 2022. Because these payments represent unconditional payment obligations, the Company recognized its liability for these payments at their net present value at discount rate of 9.72% based on the Company’s effective borrowing rate. The Manufacturing and Development Payments liability is accreted through interest expense based on the estimated timing of its ultimate settlement. As of December 31, 2016, the Company had paid $3.4 million (€3.1 million) and accrued $4.8 million (€4.5 million) related to the Manufacturing and Development Payments, which was included in “Manufacturing and development obligations - non-current” on the Company’s Consolidated Balance Sheets. As of December 31, 2015, the Company had accrued $7.8 million (€7.2 million) related to the Manufacturing and Development Payments, of which $3.3 million (€3.0 million) was included in “Manufacturing and development obligations - current”, and $4.5 million (€4.2 million) was included in “Manufacturing and development obligations - non-current” on the Company’s Consolidated Balance Sheets. The Manufacturing and Development Payments will be made to support certain projects Fresenius will perform on behalf of the Company related to R&D activities and manufacturing efficiency activities. The Company allocated $4.8 million to R&D activities and $2.4 million to manufacturing efficiency activities based on their market value in October 2015. The prepaid asset related to amounts paid up front for the R&D activities to be conducted by Fresenius on behalf of the Company is expensed over the period which such activities occur. The manufacturing efficiency asset is expensed on a straight line basis over the life of the 2015 Agreement. As of December 31, 2016, the prepaid asset related to amounts paid up front for the R&D activities to be conducted by Fresenius on behalf of the Company was included in “Other current assets” and “Other assets” on the Company’s Consolidated Balance Sheets at $0.9 million and $2.0 million, respectively. As of December 31, 2015, the prepaid asset related to amounts paid up front for the R&D activities to be conducted by Fresenius on behalf of the Company was included in “Other current assets” on the Company’s Consolidated Balance Sheets at $4.1 million. As of December 31, 2016 and December 31, 2015, the manufacturing efficiency asset was included in “Other assets” on the Company’s Consolidated Balance Sheets at $2.1 million and $2.4 million, respectively. The initial term of the 2015 Agreement extends through July 1, 2025 (the “Initial Term”) and is automatically renewed thereafter for additional two year terms (each, a “Renewal Term”), subject to termination by either party upon (i) two years written notice prior to the expiration of the Initial Term or (ii) one year written notice prior to the expiration of any Renewal Term. Under the 2015 Agreement, the Company has the right, but not the obligation, to purchase certain assets and assume certain liabilities from Fresenius. The Company made payments to Fresenius of $16.1 million, $14.9 million and $19.1 million relating to the manufacturing of the Company products during the years ended December 31, 2016, 2015 and 2014, respectively. At December 31, 2016 and December 31, 2015, the Company owed Fresenius $3.0 million and $2.5 million, respectively, for INTERCEPT disposable kits manufactured. At December 31, 2016 and December 31, 2015, amounts due from Fresenius were $0.3 million and $0.2 million, respectively. Agreement with BARDA In June 2016, the Company entered into an agreement with the Biomedical Advanced Research and Development Authority (“BARDA”) to support the Company’s development and implementation of pathogen reduction technology for platelet, plasma, and red blood cells. The five-year agreement with BARDA includes a base period (the “Base Period”) and options (each an “Option Period”) with committed funding of up to $41.6 million for clinical development of the INTERCEPT Blood System for red blood cells (the “red blood cell system”) and subsequent Option Periods that, if exercised by BARDA and completed, would bring the total funding opportunity to $185.0 million over the five-year contract period. If exercised by BARDA, subsequent options would fund activities related to broader implementation of the platelet and plasma system or the red blood cell system in areas of Zika virus risk, clinical and regulatory development programs in support of the potential licensure of the red blood cell system in the U.S., and development, manufacturing and scale-up activities for the red blood cell system. The Company would be responsible for co-investment of up to $15.0 million, if certain options were to be exercised. BARDA will make periodic assessments of the Company’s progress and the continuation of the agreement is based on the Company’s success in completing the required tasks under the Base Period and each Option Period (if and to the extent any Option Periods are exercised by BARDA). BARDA has rights under certain contract clauses to terminate the agreement, including the ability to terminate the agreement for convenience at any time. Under the contract, the Company is reimbursed and recognizes revenue as allowable direct contract costs are incurred plus allowable indirect costs, based on approved provisional indirect billing rates, which permit recovery of fringe benefits, overhead and general and administrative expenses. As of December 31, 2016 and 2015, $1.0 million and zero, respectively, was included in accounts receivable on the Company’s Consolidated Balance Sheets.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Income Taxes	Note 16. Income Taxes U.S and foreign components of consolidated loss before income taxes for the years ended December 31, 2016, 2015 and 2014, was as follows (in thousands): 2016 2015 2014 Loss before income taxes: U.S. $ (63,246 ) $ (59,897 ) $ (38,928 ) Foreign 515 358 368 Loss before income taxes $ (62,731 ) $ (59,539 ) $ (38,560 ) The provision for income taxes for the years ended December 31, 2016, 2015 and 2014, was as follows (in thousands): 2016 2015 2014 Provision for income taxes: Current: Foreign $ 147 $ 147 $ 168 Federal — — — State — — 1 Total current 147 147 169 Deferred: Foreign — — — Federal 28 (3,750 ) 22 State — (68 ) 4 Total deferred 28 (3,818 ) 26 Provision (benefit) for income taxes $ 175 $ (3,671 ) $ 195 The difference between the provision for income taxes and the amount computed by applying the federal statutory income tax rate to loss before taxes for the years ended December 31, 2016, 2015 and 2014, was as follows (in thousands): 2016 2015 2014 Federal statutory tax $ (21,329 ) $ (20,243 ) $ (13,110 ) Warrants — (3,565 ) (3,367 ) Expiration of federal loss carryovers — 3,337 — Change in valuation allowance 13,589 11,754 16,576 Change in state apportionment — 4,085 — Revision to prior year items 7,551 — — Other 364 961 96 Provision (benefit) for income taxes $ 175 $ (3,671 ) $ 195 On December 31, 2015, the California Supreme Court issued a decision disallowing the use of an income apportionment method pursuant to the Multistate Tax Compact. On October 10, 2016, the U.S Supreme Court decided not to hear an appeal of this decision. Previously the Company had relied on lower court decisions allowing the use of this apportionment method to file its 2013 and 2014 tax returns and to determine its deferred tax balances. Based on the California Supreme Court decision, the Company adjusted the apportionment for its deferred tax balances and the respective valuation allowance as of December 31, 2015. During 2016 the Company reviewed its cumulative research tax credits and tax losses. As part of this review, revisions were made to the amounts as originally estimated which are reflected in the deferred tax balances and the respective valuation allowance as of December 31, 2016. Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes at the enacted rates. The significant components of the Company’s deferred tax assets and liabilities at December 31, 2016 and 2015, were as follows (in thousands): December 31, 2016 2015 Deferred tax assets: Net operating loss carryforwards $ 176,490 $ 165,813 Research and development credit carryforwards 31,777 35,131 Capitalized research and development 22,575 17,916 Deferred compensation 8,242 5,908 Other 3,184 3,911 Total deferred tax assets 242,268 228,679 Valuation allowance (238,443 ) (224,854 ) Net deferred tax assets $ 3,825 $ 3,825 Deferred tax liabilities: Unrealized gain on investments $ 3,825 $ 3,825 Amortization of goodwill 150 122 Total deferred tax liabilities $ 3,975 $ 3,947 The valuation allowance increased by $13.6 million for the year ended December 31, 2016, compared to the increase of $11.8 million and $14.1 million for the years ended December 31, 2015 and 2014, respectively. The Company believes that, based on a number of factors, the available objective evidence creates sufficient uncertainty regarding the realizability of the deferred tax assets such that a valuation allowance has been recorded. These factors include the Company’s history of net losses since its inception, the need for regulatory approval of the Company’s products prior to commercialization, expected near-term future losses and the absence of taxable income in prior carryback years. The Company expects to maintain a valuation allowance until circumstances change. Undistributed earnings of the Company’s foreign subsidiary, Cerus Europe B.V., amounted to approximately $5.2 million at December 31, 2016. The earnings are considered to be permanently reinvested and accordingly, no deferred U.S. income taxes have been provided thereon. Upon distribution of those earnings in the form of dividends or otherwise, the Company would be subject to U.S. income taxes. The unrecognized deferred tax liability for unrepatriated earnings at December 31, 2016, was approximately $1.9 million. In the event all foreign undistributed earnings were remitted to the U.S., the Company believes any incremental tax liability would be offset by the Company’s domestic net operating losses and credits. For the year ended December 31, 2016, the Company reported pretax net losses of $62.7 million on its consolidated statement of operations and calculated taxable losses for both federal and state taxes. The difference between reported net loss and taxable loss are due to differences between book accounting and the respective tax laws. At December 31, 2016, the Company had federal and state net operating loss carryforwards of approximately $503 million and $94 million, respectively. The net operating loss carryforwards for federal and state expire at various dates beginning in 2017 through 2036. The Company’s net operating losses do not include $2.8 million related to windfall tax deductions associated with stock based compensation. The stock based compensation windfall deductions, if utilized, would serve to reduce any income taxes payable with a corresponding credit to additional paid in capital. At December 31, 2016, the Company had federal research and development credit carryforwards of approximately $23.9 million that expire in various years between 2018 and 2036. The California research and development credits are approximately $11.9 million as of December 31, 2016, and have an indefinite carryover period. The utilization of net operating loss carryforwards, as well as research and development credit carryforwards, is limited by current tax regulations. These net operating loss carryforwards, as well as research and development credit carryforwards, will be utilized in future periods if sufficient income is generated. The Company’s ability to utilize certain loss carryforwards and certain research credit carryforwards are subject to limitations pursuant to the ownership change rules in accordance with Section 382 of the Internal Revenue Code of 1986 and with Section 383 of the Internal Revenue Code of 1986, as well as similar state provisions. The Company’s unrecognized tax benefits relate to federal and California research tax credits. These tax credits have not been utilized on any tax return and currently have no impact on the Company’s tax expense due to the Company’s operating losses and the related valuation allowances. The following is a tabular reconciliation of the total amounts of unrecognized tax benefits (in thousands): December 31, 2016 Unrecognized tax benefits at beginning of period $ — Increases related to prior year tax positions 10,691 Increases related to current year tax positions 145 Unrecognized tax benefits at beginning of period $ 10,836 The Company will recognize accrued interest and penalties related to unrecognized tax benefits in its income tax expense. To date, the Company has not recognized any interest and penalties in its consolidated statements of operations, nor has it accrued for or made payments for interest and penalties. The Company’s federal tax years 1998 through 2015 and California tax years through 2015 remain subject to examination by the taxing jurisdictions due to unutilized net operating losses and research credits. The Netherlands tax returns of our Cerus Europe B.V. subsidiary for the years 2013 through 2015 are still subject to examination. There was no income tax audit activity in 2015 nor has the Company been notified by any tax agency of any planned audits.

Segment, Customer and Geographi

Segment, Customer and Geographic Information	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
Segment, Customer and Geographic Information	Note 17. Segment, Customer and Geographic Information The Company continues to operate in only one segment, blood safety. The Company’s chief executive officer is the chief operating decision maker who evaluates performance based on the net revenues and operating loss of the blood safety segment. The Company considers the sale of all of its INTERCEPT Blood System products to be similar in nature and function, and any revenue earned from services is minimal. The Company’s operations outside of the U.S. include a wholly-owned subsidiary headquartered in Europe. The Company’s operations in the U.S. are responsible for the research and development and global and domestic commercialization of the INTERCEPT Blood System, while operations in Europe are responsible for the commercialization efforts of the platelet and plasma systems in Europe, the Commonwealth of Independent States and the Middle East. Product revenues are attributed to each region based on the location of the customer, and in the case of non-product revenues, on the location of the collaboration partner. The Company had the following significant customers that accounted for more than 10% of the Company’s total product revenue, all of which operate in a country outside of the U.S., during the years ended December 31, 2016, 2015 and 2014 (in percentages): Year Ended December 31, 2016 2015 2014 Advanced Technology 12% * * Etablissement Francais du Sang * 23% 25% * Represents an amount less than 10% of product revenue. Revenues by geographical location was based on the location of the customer during the years ended December 31, 2016, 2015 and 2014, and was as follows (in thousands): Year Ended December 31, 2016 2015 2014 Product revenue: Belgium $ 6,392 $ 5,728 $ 4,456 United States 4,480 563 350 Kuwait 4,415 1,959 2,557 France 3,485 7,732 9,184 Spain and Portugal 3,360 4,070 2,776 Switzerland 3,324 2,938 3,784 CIS 2,859 3,361 6,636 Other countries 8,868 7,872 6,673 Total product revenue 37,183 34,223 36,416 Government contracts revenue: United States 2,092 — — Total government contracts revenue 2,092 — — Total revenue $ 39,275 $ 34,223 $ 36,416 Long-lived assets by geographical location, which consist of property and equipment, net and intangible assets, net, at December 31, 2016 and 2015, were as follows (in thousands): December 31, 2016 2015 U.S. and territories $ 3,529 $ 4,260 Europe & other 194 229 Total long-lived assets $ 3,723 $ 4,489

Quarterly Financial Information

Quarterly Financial Information (Unaudited)	12 Months Ended
	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Information (Unaudited)	Note 18. Quarterly Financial Information (Unaudited) The following tables summarize the Company’s quarterly financial information for the years ended December 31, 2016 and 2015 (in thousands except per share amounts): Three Months Ended March 31, 2016 June 30, 2016 September 30, 2016 December 31, 2016 Product revenue $ 7,632 $ 9,251 $ 10,175 $ 10,125 Gross profit on product revenue 3,369 4,275 4,724 4,520 Government contracts revenue — — 261 1,831 Net loss (16,863 ) (18,166 ) (14,376 ) (13,501 ) Net loss per share: Basic (0.17 ) (0.18 ) (0.14 ) (0.13 ) Diluted (0.17 ) (0.18 ) (0.14 ) (0.13 ) Three Months Ended March 31, 2015 June 30, 2015 September 30, 2015 December 31, 2015 Product revenue $ 7,692 $ 8,830 $ 8,045 $ 9,656 Gross profit on product revenue 2,978 1,802 2,485 3,494 Government contracts revenue — — — — Net loss (9,460 ) (15,972 ) (15,680 ) (14,756 ) Net loss per share: Basic (0.10 ) (0.17 ) (0.16 ) (0.15 ) Diluted (0.17 ) (0.17 ) (0.17 ) (0.15 )

Summary of Significant Accoun27

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation The accompanying consolidated financial statements include those of Cerus Corporation and its subsidiary, Cerus Europe B.V. (together with Cerus Corporation, hereinafter “Cerus” or the “Company”) after elimination of all intercompany accounts and transactions. These consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the U.S. (“GAAP”) and pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”).
Use of Estimates	Use of Estimates The preparation of financial statements requires management to make estimates, assumptions and judgments that affect the reported amounts of assets, liabilities, revenue and expenses, and related disclosures of contingent assets and liabilities. On an ongoing basis, management evaluates its estimates, including those related to the accounts receivable, inventory reserves, fair values of investments, stock-based compensation, intangible assets and goodwill, useful lives of intangible assets and property and equipment, income taxes, and accrued liabilities, among others. We base our estimates on historical experience, future projections, and on various other assumptions that are believed to be reasonable under the circumstances. Actual results may differ from those estimates under different assumptions or conditions.
Revenue	Revenue The Company recognizes revenue in accordance with Accounting Standards Codification (“ASC”) Topic 605-25, “Revenue Recognition – Arrangements with Multiple Deliverables,” Revenue related to product sales is generally recognized when the Company fulfills its obligations for each element of an agreement. For all sales of the Company’s INTERCEPT Blood System products, the Company uses a binding purchase order or signed sales contract as evidence of an arrangement. The Company sells its platelet and plasma systems directly to blood banks, hospitals, universities, government agencies, as well as to distributors in certain regions. Generally, the Company’s contracts with its customers do not provide for open return rights, except within a reasonable time after receipt of goods in the case of defective or non-conforming product. Deliverables and the units of accounting vary according to the provisions of each purchase order or sales contract. For revenue arrangements with multiple elements, the Company determines whether the delivered elements meet the criteria as separate units of accounting. Such criteria require that the deliverable have stand-alone value to the customer and that if a general right of return exists relative to the delivered item, delivery or performance of the undelivered item(s) is considered probable and substantially in the control of the Company. Once the Company determines if the deliverable meets the criteria for a separate unit of accounting, the Company must determine how the consideration should be allocated between the deliverables and how the separate units of accounting should be recognized as revenue. Consideration received is allocated to elements that are identified as discrete units of accounting. Because the Company has no vendor specific objective evidence or third party evidence for its systems due to the Company’s variability in its pricing across the regions into which it sells its products, the allocation of revenue is based on best estimated selling price for the products sold. The objective of best estimated selling price is to determine the price at which the Company would transact a sale, had the product been sold on a stand-alone basis. The Company determines best estimated selling price for its systems by considering multiple factors. The Company regularly reviews best estimated selling price. At December 31, 2016 and 2015, the Company had $0.1 million and $0.6 million, respectively, of short-term deferred revenue on its consolidated balance sheets related to future performance obligations. At each of December 31, 2016 and 2015, the Company had $0.1 million of long-term deferred revenue included in “Other non-current liabilities” on it consolidated balance sheets related to future performance obligations. Freight costs charged to customers are recorded as a component of revenue. Taxes that the Company invoices to its customers and remits to governments are recorded on a net basis, which excludes such tax from product revenue. The Company receives reimbursement under its U.S. government contract that supports research and development of defined projects. The contract generally provides for reimbursement of approved costs incurred under the terms of the applicable contract. Revenue related to the cost reimbursement provisions under U.S. government contract are recognized as the qualified direct and indirect costs on the projects are incurred. The Company invoices under its U.S. government contract using the provisional rates in the government contract and thus is subject to future audits at the discretion of government. These audits could result in an adjustment to revenue previously reported, which adjustments potentially could be significant. The Company believes that revenue for periods not yet audited has been recorded in amounts that are expected to be realized upon final audit and settlement. Costs incurred related to services performed under the contract are included as a component of research and development or selling, general and administrative expenses in the Company’s consolidated statements of operations. The Company’s use of estimates in recording accrued liabilities for government contract activities (see “Use of Estimates” above) affects the revenue recorded from development funding and government contract.
Research and Development Expenses	Research and Development Expenses In accordance with ASC Topic 730, “Accounting for Research and Development Expenses,” The Company’s use of estimates in recording accrued liabilities for R&D activities (see “Use of Estimates” above) affects the amounts of R&D expenses recorded from development funding and government contract. Actual results may differ from those estimates under different assumptions or conditions.
Cash Equivalents	Cash Equivalents The Company considers all highly liquid investments with original maturities of three months or less from the date of purchase to be classified as cash equivalents. These investments primarily consist of money market instruments, and are classified as available-for-sale.
Investments	Investments Investments with original maturities of greater than three months primarily include corporate debt and U.S. government agency securities, and marketable equity securities of Aduro Biotech, Inc. (“Aduro”) are designated as available-for-sale and classified as short-term investments or investment in marketable equity securities, in accordance with ASC Topic 320, “ Accounting for Certain Investments in Debt and Equity Securities The Company also reviews its available-for-sale securities on a regular basis to evaluate whether any security has experienced an other-than-temporary decline in fair value. Other-than-temporary declines in market value, if any, are recorded in “Other income, net” on the Company’s consolidated statements of operations.
Restricted Cash	Restricted Cash Prior to December 31, 2016, the Company held a certificate of deposit with a domestic bank for any potential decommissioning resulting from the Company’s possession of radioactive material. The certificate of deposit was held to satisfy the financial surety requirements of the California Department of Health Services and was recorded in “Restricted cash” on the Company’s condensed consolidated balance sheets at December 31, 2015. As of December 31, 2016, the Company also had certain non-U.S. dollar denominated deposits recorded as “Restricted cash” in compliance with certain foreign contractual requirements.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash equivalents, available-for-sale securities and accounts receivable. Pursuant to the Company’s investment policy, substantially all of the Company’s cash, cash equivalents and available-for-sale securities are maintained at major financial institutions of high credit standing. The Company monitors the financial credit worthiness of the issuers of its investments and limits the concentration in individual securities and types of investments that exist within its investment portfolio. Generally, all of the Company’s investments carry high credit quality ratings, which is in accordance with its investment policy. At December 31, 2016, the fair value of the Company’s marketable equity securities of Aduro is subject to the underlying volatility of Aduro’s stock price. At December 31, 2016, the Company does not believe there is significant financial risk from non-performance by the issuers of the Company’s cash equivalents and short-term investments. Concentrations of credit risk with respect to trade receivables exist. On a regular basis, including at the time of sale, the Company performs credit evaluations of its significant customers that it expects to sell to on credit terms. Generally, the Company does not require collateral from its customers to secure accounts receivable. To the extent that the Company determines specific invoices or customer accounts may be uncollectible, the Company establishes an allowance for doubtful accounts against the accounts receivable on its consolidated balance sheets and records a charge on its consolidated statements of operations as a component of selling, general and administrative expenses. The Company had three customers that accounted for more than 10% of the Company’s outstanding trade receivables at both December 31, 2016 and 2015. These customers cumulatively represented approximately 46% and 49% of the Company’s outstanding trade receivables at December 31, 2016 and 2015, respectively. To date, the Company has not experienced collection difficulties from these customers.
Inventories	Inventories At December 31, 2016 and 2015, inventory consisted of work-in-process and finished goods only. Finished goods include INTERCEPT disposable kits, illuminators, and certain replacement parts for the illuminators. Platelet and plasma systems’ disposable kits generally have a two-year life from the date of manufacture. Illuminators and replacement parts do not have regulated expiration dates. Work-in-process includes certain components that are manufactured over a protracted length of time before being sold to, and ultimately incorporated and assembled by Fresenius Kabi Deutschland GmbH or Fresenius, Inc. (with their affiliates, “Fresenius”) into the finished INTERCEPT disposable kits. The Company maintains an inventory balance based on its current sales projections, and at each reporting period, the Company evaluates whether its work-in-process inventory would be sold to Fresenius for production of finished units in order to sell to existing and prospective customers within the next twelve-month period. It is not customary for the Company’s production cycle for inventory to exceed twelve months. Instead, the Company uses its best judgment to factor in lead times for the production of its work-in-process and finished units to meet the Company’s forecasted demands. If actual results differ from those estimates, work-in-process inventory could potentially accumulate for periods exceeding one year. At December 31, 2016 and 2015, the Company classified its work-in-process inventory as a current asset on its consolidated balance sheets based on its evaluation that the work-in-process inventory would be sold to Fresenius for finished disposable kit production within each respective subsequent twelve-month period. Inventory is recorded at the lower of cost, determined on a first-in, first-out basis, or net realizable value. The Company uses significant judgment to analyze and determine if the composition of its inventory is obsolete, slow-moving or unsalable and frequently reviews such determinations. The Company writes down specifically identified unusable, obsolete, slow-moving, or known unsalable inventory that has no alternative use in the period that it is first recognized by using a number of factors including product expiration dates, open and unfulfilled orders, and sales forecasts. Any write-down of its inventory to net realizable value establishes a new cost basis and will be maintained even if certain circumstances suggest that the inventory is recoverable in subsequent periods. Costs associated with the write-down of inventory are recorded in “Cost of product revenue” on the Company’s consolidated statements of operations. At December 31, 2016, and 2015, the Company had $0.2 million and $1.8 million, respectively, recorded for potential obsolete, expiring or unsalable product.
Property and Equipment, net	Property and Equipment, net Property and equipment is comprised of furniture, equipment, leasehold improvements, construction-in-progress, information technology hardware and software and is recorded at cost. At the time the property and equipment is ready for its intended use, it is depreciated on a straight-line basis over the estimated useful lives of the assets (generally three to five years). Leasehold improvements are amortized on a straight-line basis over the shorter of the lease term or the estimated useful lives of the improvements.
Capitalization of Software Costs	Capitalization of Software Costs The Company capitalizes certain significant costs incurred in the acquisition and development of software for internal use, including the costs of the software, materials, and consultants during the application development stage. Costs incurred prior to the application development stage, costs incurred once the application is substantially complete and ready for its intended use, and other costs not qualifying for capitalization, including training and maintenance costs, are charged to expense as incurred.
Goodwill and Intangible Assets, net	Goodwill and Intangible Assets, net Intangible assets, net, which include a license for the right to commercialize the INTERCEPT Blood System in Asia, are subject to ratable amortization over the original estimated useful life of ten years. The amortization of the Company’s intangible assets, net, is recorded in “Amortization of intangible assets” on the Company’s consolidated statements of operations. Goodwill is not amortized but instead is subject to an impairment test performed on an annual basis, or more frequently if events or changes in circumstances indicate that goodwill may be impaired. Such impairment analysis is performed on August 31 of each fiscal year, or more frequently if indicators of impairment exist. The test for goodwill impairment may be assessed using qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than the carrying amount. If the Company determines that it is more likely than not that the fair value of a reporting unit is less than the carrying amount, the Company must then proceed with performing the quantitative two-step process to test goodwill for impairment; otherwise, goodwill is not considered impaired and no further testing is warranted. The Company may choose not to perform the qualitative assessment to test goodwill for impairment and proceed directly to the quantitative two-step process; however, the Company may revert to the qualitative assessment to test goodwill for impairment in any subsequent period. The first step of the two-step process compares the fair value of each reporting unit with its respective carrying amount, including goodwill. The Company has determined that it operates in one reporting unit and estimates the fair value of its one reporting unit using the enterprise approach under which it considers the quoted market capitalization of the Company as reported on the Nasdaq Global Market. The Company considers quoted market prices that are available in active markets to be the best evidence of fair value. The Company also considers other factors, which include future forecasted results, the economic environment and overall market conditions. If the fair value of the reporting unit exceeds its carrying amount, goodwill of the reporting unit is not considered impaired and, therefore, the second step of the impairment test is unnecessary. The second step of the two-step process, which is used to measure the amount of impairment loss, compares the implied fair value of each reporting unit’s goodwill, based on the present value of future cash flows, with the respective carrying amount of that goodwill. If the carrying amount of the reporting unit’s goodwill exceeds the implied fair value of that goodwill, an impairment loss is recognized in an amount equal to that excess. The Company performs an impairment test on its intangible assets, in accordance ASC Topic 360-10, “Property, Plant and Equipment,”
Long-lived Assets	Long-lived Assets The Company evaluates its long-lived assets for impairment by continually monitoring events and changes in circumstances that could indicate carrying amounts of its long-lived assets may not be recoverable. When such events or changes in circumstances occur, the Company assesses recoverability by determining whether the carrying value of such assets will be recovered through the undiscounted expected future cash flows. If the expected undiscounted future cash flows are less than the carrying amount of these assets, the Company then measures the amount of the impairment loss based on the excess of the carrying amount over the fair value of the assets.
Foreign Currency Remeasurement	Foreign Currency Remeasurement The functional currency of the Company’s foreign subsidiary is the U.S. dollar. Monetary assets and liabilities denominated in foreign currencies are remeasured in U.S. dollars using the exchange rates at the balance sheet date. Non-monetary assets and liabilities denominated in foreign currencies are remeasured in U.S. dollars using historical exchange rates. Revenues and expenses are remeasured using average exchange rates prevailing during the period. Remeasurements are recorded in the Company’s consolidated statements of operations.
Stock-Based Compensation	Stock-Based Compensation The Company accounts for stock-based compensation in accordance with ASC Topic 718, Compensation - Stock Compensation. For stock-based awards issued to non-employees, the Company follows ASC Topic 505-50, Equity Based Payment to Non-Employees See Note 13 for further information regarding the Company’s stock-based compensation assumptions and expenses.
Income Taxes	Income Taxes The Company accounts for income taxes using an asset and liability approach in accordance with ASC Topic 740, Accounting for Income Taxes
Net Loss Per Share	Net Loss Per Share Basic net loss per share is computed by dividing net loss by the weighted average number of common shares outstanding for the period. Diluted net loss per share gives effect to all potentially dilutive common shares outstanding for the period. The potentially dilutive securities include stock options, employee stock purchase plan rights, warrants and restricted stock units, which are calculated using the treasury stock method. Diluted net loss per share also gives effect to potential adjustments to the numerator for gains resulting from the revaluation of warrants to fair value for the period, even if the Company is in a net loss position if the effect would result in more dilution. Certain potential dilutive securities were excluded from the dilution calculation for the years ended December 31, 2016, 2015 and 2014, as their inclusion would have been anti-dilutive. The following table sets forth the reconciliation of the numerator and denominator used in the computation of basic and diluted net loss per share for the years ended December 31, 2016, 2015 and 2014 (in thousands, except per share amounts): Year Ended December 31, 2016 2015 2014 Numerator for Basic and Diluted: Net loss used for basic calculation $ (62,906 ) $ (55,868 ) $ (38,755 ) Effect of revaluation of warrant liability — (3,566 ) (7,708 ) Adjusted net loss used for dilution calculation $ (62,906 ) $ (59,434 ) $ (46,463 ) Denominator: Basic weighted average number of shares outstanding 101,826 96,068 74,767 Effect of dilutive potential shares — 837 1,767 Diluted weighted average number of shares outstanding 101,826 96,905 76,534 Net loss per share: Basic $ (0.62 ) $ (0.58 ) $ (0.52 ) Diluted (0.62 ) (0.61 ) (0.61 ) The table below presents shares underlying stock options and restricted stock units that were excluded from the calculation of the weighted average number of shares outstanding used for the calculation of diluted net loss per share. These are excluded from the calculation due to their anti-dilutive effect for the years ended December 31, 2016, 2015 and 2014 (shares in thousands): Year Ended December 31, 2016 2015 2014 Weighted average number of anti-dilutive potential shares: Stock options 15,592 13,681 11,722 Restricted stock units 576 — — Total 16,168 13,681 11,722
Guarantee and Indemnification Arrangements	Guarantee and Indemnification Arrangements The Company recognizes the fair value for guarantee and indemnification arrangements issued or modified by the Company. In addition, the Company monitors the conditions that are subject to the guarantees and indemnifications in order to identify if a loss has occurred. If the Company determines it is probable that a loss has occurred, then any such estimable loss would be recognized under those guarantees and indemnifications. Some of the agreements that the Company is a party to contain provisions that indemnify the counter party from damages and costs resulting from claims that the Company’s technology infringes the intellectual property rights of a third party or claims that the sale or use of the Company’s products have caused personal injury or other damage or loss. The Company has not received any such requests for indemnification under these provisions and has not been required to make material payments pursuant to these provisions. The Company generally provides for a one-year warranty on certain of its INTERCEPT blood-safety products covering defects in materials and workmanship. The Company accrues costs associated with warranty obligations when claims become known and are estimable. The Company has not experienced significant or systemic warranty claims nor is it aware of any existing current warranty claims. Accordingly, the Company had not accrued for any future warranty costs for its products at December 31, 2016 and 2015.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The Company applies the provisions of fair value relating to its financial assets and liabilities. The carrying amounts of accounts receivables, accounts payable, and other accrued liabilities approximate their fair value due to the relative short-term maturities. Based on the borrowing rates currently available to the Company for loans with similar terms, the Company believes the fair value of its debt approximates their carrying amounts. The Company measures and records certain financial assets and liabilities at fair value on a recurring basis, including its available-for-sale securities and warrant liability prior to the expiration and exercise of the warrants in November 2015. The Company classifies instruments within Level 1 if quoted prices are available in active markets for identical assets, which include the Company’s cash accounts and money market funds. The Company classifies instruments in Level 2 if the instruments are valued using observable inputs to quoted market prices, benchmark yields, reported trades, broker/dealer quotes or alternative pricing sources with reasonable levels of price transparency. These instruments include the Company’s corporate debt and U.S. government agency securities holdings. The available-for-sale securities are held by a custodian who obtains investment prices from a third party pricing provider that uses standard inputs (observable in the market) to models which vary by asset class. The Company classifies instruments in Level 3 if one or more significant inputs or significant value drivers are unobservable. The Company assesses any transfers among fair value measurement levels at the end of each reporting period. See Notes 3 for further information regarding the Company’s valuation of financial instruments.
New Accounting Pronouncements	New Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (“FASB”) issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606), Revenue from Contracts with Customers (Topic 606), Deferral of the Effective Date Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations (Reporting Revenue Gross versus Net) Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing, Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients, Technical Corrections and Improvements to Topic 606, Revenue from Contracts with Customers In August 2014, the FASB issued ASU No. 2014-15, Presentation of Financial Statements—Going Concern In April 2015, the FASB issued ASU No. 2015-03, Interest—Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs In January 2016, the FASB issued ASU No. 2016-01, Financial Instruments-Overall (Subtopic 825-10) In February 2016, the FASB issued ASU No. 2016-02, Leases In March 2016, the FASB issued ASU No. 2016-09, Compensation-Stock Compensation (Topic 718):Improvements to Employee Share-Based Payment Accounting, In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230): Restricted Cash, a consensus of the FASB Emerging Issues Task Force, In January 2017, the FASB issued ASU No. 2017-04, Intangibles—Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment,

Summary of Significant Accoun28

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Computation of Basic and Diluted Net Loss per Share	The following table sets forth the reconciliation of the numerator and denominator used in the computation of basic and diluted net loss per share for the years ended December 31, 2016, 2015 and 2014 (in thousands, except per share amounts): Year Ended December 31, 2016 2015 2014 Numerator for Basic and Diluted: Net loss used for basic calculation $ (62,906 ) $ (55,868 ) $ (38,755 ) Effect of revaluation of warrant liability — (3,566 ) (7,708 ) Adjusted net loss used for dilution calculation $ (62,906 ) $ (59,434 ) $ (46,463 ) Denominator: Basic weighted average number of shares outstanding 101,826 96,068 74,767 Effect of dilutive potential shares — 837 1,767 Diluted weighted average number of shares outstanding 101,826 96,905 76,534 Net loss per share: Basic $ (0.62 ) $ (0.58 ) $ (0.52 ) Diluted (0.62 ) (0.61 ) (0.61 )
Anti-Dilutive Effect of Common Shares	The table below presents shares underlying stock options and restricted stock units that were excluded from the calculation of the weighted average number of shares outstanding used for the calculation of diluted net loss per share. These are excluded from the calculation due to their anti-dilutive effect for the years ended December 31, 2016, 2015 and 2014 (shares in thousands): Year Ended December 31, 2016 2015 2014 Weighted average number of anti-dilutive potential shares: Stock options 15,592 13,681 11,722 Restricted stock units 576 — — Total 16,168 13,681 11,722

Fair Value on Financial Instr29

Fair Value on Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Fair Values of Financial Assets and Liabilities	The fair values of the Company’s financial assets and liabilities were determined using the following inputs at December 31, 2016 (in thousands): Balance sheet Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs classification Total (Level 1) (Level 2) (Level 3) Money market funds Cash and cash equivalents $ 8,991 $ 8,991 $ — $ — United States government agency securities Short-term investments 8,029 — 8,029 — Corporate debt securities Short-term investments 37,087 — 37,087 — Marketable equity securities Marketable equity securities 3,952 3,952 — — Total financial assets $ 58,059 $ 12,943 $ 45,116 $ — The fair values of the Company’s financial assets and liabilities were determined using the following inputs at December 31, 2015 (in thousands): Balance sheet Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs classification Total (Level 1) (Level 2) (Level 3) Money market funds Cash and cash equivalents $ 59,302 $ 59,302 $ — $ — Corporate debt securities Short-term investments 25,698 — 25,698 — Marketable equity securities Marketable equity securities 11,163 11,163 — — Total financial assets $ 96,163 $ 70,465 $ 25,698 $ —
Reconciliation of Fair Value Measurement on Liabilities Using Significant Unobservable Inputs	A reconciliation of the beginning and ending balances for the warrant liability using significant unobservable inputs (Level 3) from December 31, 2014 to December 31, 2015, was as follows (in thousands): Balance at December 31, 2014 $ 10,485 Decrease in fair value of warrants (3,566 ) Settlement of warrants exercised (6,919 ) Balance at December 31, 2015 $ —

Available-for-sale Securities (

Available-for-sale Securities (Tables)	12 Months Ended
	Dec. 31, 2016
Investments Debt And Equity Securities [Abstract]
Summary of Available-for-Sale Securities	The following is a summary of available-for-sale securities at December 31, 2016 (in thousands): December 31, 2016 Amortized Cost Gross Unrealized Gain Gross Unrealized Loss Fair Value Money market funds $ 8,991 $ — $ — $ 8,991 United States government agency securities 8,030 — (1 ) 8,029 Corporate debt securities 37,110 — (23 ) 37,087 Marketable equity securities — 3,952 — 3,952 Total available-for-sale securities $ 54,131 $ 3,952 $ (24 ) $ 58,059 The following is a summary of available-for-sale securities at December 31, 2015(in thousands): December 31, 2015 Amortized Cost Gross Unrealized Gain Gross Unrealized Loss Fair Value Money market funds $ 59,302 $ — $ — $ 59,302 Corporate debt securities 25,747 — (49 ) 25,698 Marketable equity securities — 11,163 — 11,163 Total available-for-sale securities $ 85,049 $ 11,163 $ (49 ) $ 96,163
Available-for-Sale Debt Securities by Original Contractual Maturity	Available-for-sale securities at December 31, 2016 and 2015, consisted of the following by contractual maturity (in thousands): December 31, 2016 December 31, 2015 Amortized Cost Fair Value Amortized Cost Fair Value One year or less $ 54,131 $ 54,107 $ 85,049 $ 85,000 Marketable equity securities — 3,952 — 11,163 Greater than one year and less than five years — — — — Total available-for-sale securities $ 54,131 $ 58,059 $ 85,049 $ 96,163
Available-for-Sale Marketable Securities in Unrealized Position	The following tables show all available-for-sale marketable securities in an unrealized loss position for which an other-than-temporary impairment has not been recognized and the related gross unrealized losses and fair value, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position (in thousands): December 31, 2016 Less than 12 Months 12 Months or Greater Total Fair Value Unrealized Loss Fair Value Unrealized Loss Fair Value Unrealized Loss Money market funds $ — $ — $ — $ — $ — $ — United States government agency securities 6,035 (1 ) — — 6,035 (1 ) Corporate debt securities 34,086 (23 ) — — 34,086 (23 ) Total available-for-sale securities $ 40,121 $ (24 ) $ — $ — $ 40,121 $ (24 ) December 31, 2015 Less than 12 Months 12 Months or Greater Total Fair Value Unrealized Loss Fair Value Unrealized Loss Fair Value Unrealized Loss Money market funds $ — $ — $ — $ — $ — $ — United States government agency securities — — — — — — Corporate debt securities 20,170 (46 ) 5,528 (3 ) 25,698 (49 ) Total available-for-sale securities $ 20,170 $ (46 ) $ 5,528 $ (3 ) $ 25,698 $ (49 )

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Dec. 31, 2016
Inventory Disclosure [Abstract]
Inventories	Inventories at December 31, 2016 and 2015, consisted of the following (in thousands): December 31, 2016 2015 Work-in-process $ 5,044 $ 3,187 Finished goods 7,487 7,625 Total inventories $ 12,531 $ 10,812

Property and Equipment, net (Ta

Property and Equipment, net (Tables)	12 Months Ended
	Dec. 31, 2016
Property Plant And Equipment [Abstract]
Property and Equipment, Net	Property and equipment, net at December 31, 2016 and 2015, consisted of the following (in thousands): December 31, 2016 2015 Leasehold improvements $ 5,678 $ 5,678 Machinery and equipment 1,925 1,603 Demonstration equipment 167 145 Furniture and fixtures 871 794 Computer equipment 603 591 Computer software 2,908 2,935 Consigned equipment 1,058 1,010 Construction-in-progress 62 219 Total property and equipment, gross 13,272 12,975 Accumulated depreciation and amortization (10,287 ) (9,426 ) Total property and equipment, net $ 2,985 $ 3,549

Goodwill and Intangible Asset33

Goodwill and Intangible Assets, net (Tables)	12 Months Ended
	Dec. 31, 2016
Goodwill And Intangible Assets Disclosure [Abstract]
Summary of Intangible Assets	The following is a summary of intangible assets, net at December 31, 2016 (in thousands): December 31, 2016 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Acquisition-related intangible assets: Reacquired license - INTERCEPT Asia $ 2,017 $ (1,279 ) $ 738 Total intangible assets $ 2,017 $ (1,279 ) $ 738 The following is a summary of intangible assets, net at December 31, 2015 (in thousands): December 31, 2015 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Acquisition-related intangible assets: Reacquired license - INTERCEPT Asia $ 2,017 $ (1,077 ) $ 940 Total intangible assets $ 2,017 $ (1,077 ) $ 940

Accrued Liabilities (Tables)

Accrued Liabilities (Tables)	12 Months Ended
	Dec. 31, 2016
Payables And Accruals [Abstract]
Accrued Liabilities	Accrued liabilities at December 31, 2016 and 2015, consisted of the following (in thousands): December 31, 2016 2015 Accrued compensation and related costs $ 7,098 $ 5,198 Accrued professional services 2,511 2,337 Accrued customer costs 534 987 Accrued insurance premiums 476 438 Other accrued expenses 599 893 Total accrued liabilities $ 11,218 $ 9,853

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Debt	Debt at December 31, 2016, consisted of the following (in thousands): December 31, 2016 Principal Unamortized Discount Net Carrying Value Loan and Security Agreement $ 19,499 $ (124 ) $ 19,375 Less: debt - current (7,013 ) 79 (6,934 ) Debt - non-current $ 12,486 $ (45 ) $ 12,441 Debt at December 31, 2015, consisted of the following (in thousands): December 31, 2015 Principal Unamortized Discount Total Loan and Security Agreement $ 20,000 $ (196 ) $ 19,804 Less: debt - current (3,050 ) 94 (2,956 ) Debt - non-current $ 16,950 $ (102 ) $ 16,848
Expected Principal and Interest Payments on Debt	Principal and interest payments on debt at December 31, 2016, are expected to be as follows: Year ended December 31, Principal Interest Total 2017 7,013 1,160 8,173 2018 8,178 613 8,791 2019 4,308 1,488 5,796 Total $ 19,499 $ 3,261 $ 22,760

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2016
Commitments And Contingencies Disclosure [Abstract]
Future Minimum Non-Cancelable Lease Payments Under Operating Leases	Future minimum non-cancelable lease payments under operating leases as of December 31, 2016, are as follows (in thousands): Year ended December 31, 2017 $ 1,233 2018 868 2019 739 2020 30 2021 2 Total minimum non-cancellable lease payments $ 2,872

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2016
Information Regarding Stock Options Outstanding Stock Options Vested and Expected to Vest and Stock Options Exercisable	Information regarding the Company’s stock options outstanding, stock options vested and expected to vest, and stock options exercisable at December 31, 2016, was as follows (in thousands except weighted average exercise price and contractual term): Number Weighted Exercise Weighted Average Remaining Contractual Term (Years) Aggregate Value Balances at December 31, 2016 Stock options outstanding 15,787 $ 4.39 6.3 $ 8,696 Stock options vested and expected to vest 15,541 4.38 6.2 8,695 Stock options exercisable 10,600 4.03 5.3 8,557
Recognition of Stock-Based Compensation Expense	Stock-based compensation expense recognized on the Company’s consolidated statements of operations for the years ended December 31, 2016, 2015 and 2014, was as follows (in thousands): Year Ended December 31, 2016 2015 2014 Stock-based compensation expense by caption: Research and development $ 1,091 $ 1,260 $ 998 Selling, general and administrative 6,974 5,470 4,155 Total stock-based compensation expense $ 8,065 $ 6,730 $ 5,153
Weighted Average Assumptions Used to Value Stock-Based Awards	The weighted average assumptions used to value the Company’s stock-based awards for the years ended December 31, 2016, 2015 and 2014, was as follows: Year Ended December 31, 2016 2015 2014 Stock Options: Expected term (in years) 5.85 5.66 5.71 Estimated volatility 49% 56% 61% Risk-free interest rate 1.41% 1.55% 1.73% Expected dividend yield 0% 0% 0% Employee Stock Purchase Plan Rights: Expected term (in years) 0.76 0.75 0.76 Estimated volatility 47% 53% 52% Risk-free interest rate 0.55% 0.28% 0.10% Expected dividend yield 0% 0% 0%
2008 Equity Incentive Plan
Activity Under Equity Incentive Plans Related to Stock Options	Activity under the Company’s equity incentive plans related to stock options is set forth below (in thousands except weighted average exercise price): Number of Options Outstanding Weighted Average Exercise Price per Share Balances at December 31, 2015 14,119 $ 4.21 Granted 2,722 5.39 Forfeited (287 ) 4.93 Expired (128 ) 9.18 Exercised (639 ) 3.45 Balances at December 31, 2016 15,787 4.39
Activity Under Equity Incentive Plans Related to RSUs	Activity under the Company’s equity incentive plans related to RSUs is set forth below (in thousands except per share amounts): Number of Shares Outstanding Weighted Average Grant Date Fair Value per Share Balances at December 31, 2015 — $ — Granted 762 5.26 Forfeited (23 ) 5.06 Vested — — Balances at December 31, 2016 739 5.26

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
United States and Foreign Components of Consolidated Loss Before Income Taxes	U.S and foreign components of consolidated loss before income taxes for the years ended December 31, 2016, 2015 and 2014, was as follows (in thousands): 2016 2015 2014 Loss before income taxes: U.S. $ (63,246 ) $ (59,897 ) $ (38,928 ) Foreign 515 358 368 Loss before income taxes $ (62,731 ) $ (59,539 ) $ (38,560 )
Provision Benefit for Income Taxes	The provision for income taxes for the years ended December 31, 2016, 2015 and 2014, was as follows (in thousands): 2016 2015 2014 Provision for income taxes: Current: Foreign $ 147 $ 147 $ 168 Federal — — — State — — 1 Total current 147 147 169 Deferred: Foreign — — — Federal 28 (3,750 ) 22 State — (68 ) 4 Total deferred 28 (3,818 ) 26 Provision (benefit) for income taxes $ 175 $ (3,671 ) $ 195
Difference Between Provision for Income Taxes and Amounts Computed by Applying Federal Statutory Income Tax Rate to Loss before Taxes	The difference between the provision for income taxes and the amount computed by applying the federal statutory income tax rate to loss before taxes for the years ended December 31, 2016, 2015 and 2014, was as follows (in thousands): 2016 2015 2014 Federal statutory tax $ (21,329 ) $ (20,243 ) $ (13,110 ) Warrants — (3,565 ) (3,367 ) Expiration of federal loss carryovers — 3,337 — Change in valuation allowance 13,589 11,754 16,576 Change in state apportionment — 4,085 — Revision to prior year items 7,551 — — Other 364 961 96 Provision (benefit) for income taxes $ 175 $ (3,671 ) $ 195
Significant Components of Deferred Tax Assets and Liabilities	The significant components of the Company’s deferred tax assets and liabilities at December 31, 2016 and 2015, were as follows (in thousands): December 31, 2016 2015 Deferred tax assets: Net operating loss carryforwards $ 176,490 $ 165,813 Research and development credit carryforwards 31,777 35,131 Capitalized research and development 22,575 17,916 Deferred compensation 8,242 5,908 Other 3,184 3,911 Total deferred tax assets 242,268 228,679 Valuation allowance (238,443 ) (224,854 ) Net deferred tax assets $ 3,825 $ 3,825 Deferred tax liabilities: Unrealized gain on investments $ 3,825 $ 3,825 Amortization of goodwill 150 122 Total deferred tax liabilities $ 3,975 $ 3,947
Reconciliation of Unrecognized Tax Benefits	The following is a tabular reconciliation of the total amounts of unrecognized tax benefits (in thousands): December 31, 2016 Unrecognized tax benefits at beginning of period $ — Increases related to prior year tax positions 10,691 Increases related to current year tax positions 145 Unrecognized tax benefits at beginning of period $ 10,836

Segment, Customer and Geograp39

Segment, Customer and Geographic Information (Tables)	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
Customer that Accounted for More Than Ten Percent of Total Product Revenue	The Company had the following significant customers that accounted for more than 10% of the Company’s total product revenue, all of which operate in a country outside of the U.S., during the years ended December 31, 2016, 2015 and 2014 (in percentages): Year Ended December 31, 2016 2015 2014 Advanced Technology 12% * * Etablissement Francais du Sang * 23% 25% * Represents an amount less than 10% of product revenue.
Net Revenues and Long-Lived Assets by Geographical Location	Revenues by geographical location was based on the location of the customer during the years ended December 31, 2016, 2015 and 2014, and was as follows (in thousands): Year Ended December 31, 2016 2015 2014 Product revenue: Belgium $ 6,392 $ 5,728 $ 4,456 United States 4,480 563 350 Kuwait 4,415 1,959 2,557 France 3,485 7,732 9,184 Spain and Portugal 3,360 4,070 2,776 Switzerland 3,324 2,938 3,784 CIS 2,859 3,361 6,636 Other countries 8,868 7,872 6,673 Total product revenue 37,183 34,223 36,416 Government contracts revenue: United States 2,092 — — Total government contracts revenue 2,092 — — Total revenue $ 39,275 $ 34,223 $ 36,416 Long-lived assets by geographical location, which consist of property and equipment, net and intangible assets, net, at December 31, 2016 and 2015, were as follows (in thousands): December 31, 2016 2015 U.S. and territories $ 3,529 $ 4,260 Europe & other 194 229 Total long-lived assets $ 3,723 $ 4,489

Quarterly Financial Informati40

Quarterly Financial Information (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Quarterly Unaudited Financial Data	The following tables summarize the Company’s quarterly financial information for the years ended December 31, 2016 and 2015 (in thousands except per share amounts): Three Months Ended March 31, 2016 June 30, 2016 September 30, 2016 December 31, 2016 Product revenue $ 7,632 $ 9,251 $ 10,175 $ 10,125 Gross profit on product revenue 3,369 4,275 4,724 4,520 Government contracts revenue — — 261 1,831 Net loss (16,863 ) (18,166 ) (14,376 ) (13,501 ) Net loss per share: Basic (0.17 ) (0.18 ) (0.14 ) (0.13 ) Diluted (0.17 ) (0.18 ) (0.14 ) (0.13 ) Three Months Ended March 31, 2015 June 30, 2015 September 30, 2015 December 31, 2015 Product revenue $ 7,692 $ 8,830 $ 8,045 $ 9,656 Gross profit on product revenue 2,978 1,802 2,485 3,494 Government contracts revenue — — — — Net loss (9,460 ) (15,972 ) (15,680 ) (14,756 ) Net loss per share: Basic (0.10 ) (0.17 ) (0.16 ) (0.15 ) Diluted (0.17 ) (0.17 ) (0.17 ) (0.15 )

Summary of Significant Accoun41

Summary of Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2016USD ($)CustomerSegment	Dec. 31, 2015USD ($)Customer
Summary Of Significant Accounting Policies [Line Items]
Deferred revenue-current	$ 149,000	$ 554,000
Long-term deferred revenue	$ 100,000	$ 100,000
Number of major customers representing outstanding trade receivables | Customer	3	3
Life of inventory	2 years
Protracted length of inventory	1 year
Inventory valuation reserves	$ 200,000	$ 1,800,000
Estimated useful life of intangible assets	10 years
Number of reportable segments | Segment	1
Period of warranty	1 year
Warranty claim liability	$ 0	0
Other current assets	1,804,000	4,755,000
Other assets	4,148,000	2,579,000
Debt - current	6,934,000	2,956,000
Debt - non-current	$ 12,441,000	16,848,000
Accounting Standards Update 2015-03 | Scenario, Previously Reported
Summary Of Significant Accounting Policies [Line Items]
Other current assets		32,000
Other assets		36,000
Accounting Standards Update 2015-03 | Scenario, Adjustment
Summary Of Significant Accounting Policies [Line Items]
Other current assets		(32,000)
Other assets		(36,000)
Debt - current		(32,000)
Debt - non-current		$ (36,000)
Minimum
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of property and equipment	3 years
Maximum
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of property and equipment	5 years
Trade Accounts Receivable | Customer Concentration Risk
Summary Of Significant Accounting Policies [Line Items]
Concentration risk, percentage	46.00%	49.00%

Reconciliation of Numerator and

Reconciliation of Numerator and Denominator Used in Computation of Basic and Diluted Net Income Loss per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Numerator for Basic and Diluted:
Net loss used for basic calculation	$ (13,501)	$ (14,376)	$ (18,166)	$ (16,863)	$ (14,756)	$ (15,680)	$ (15,972)	$ (9,460)	$ (62,906)	$ (55,868)	$ (38,755)
Effect of revaluation of warrant liability										(3,566)	(7,708)
Adjusted net loss used for dilution calculation									$ (62,906)	$ (59,434)	$ (46,463)
Denominator:
Basic weighted average number of shares outstanding									101,826	96,068	74,767
Effect of dilutive potential shares										837	1,767
Diluted weighted average number of shares outstanding									101,826	96,905	76,534
Net loss per share:
Basic	$ (0.13)	$ (0.14)	$ (0.18)	$ (0.17)	$ (0.15)	$ (0.16)	$ (0.17)	$ (0.10)	$ (0.62)	$ (0.58)	$ (0.52)
Diluted	$ (0.13)	$ (0.14)	$ (0.18)	$ (0.17)	$ (0.15)	$ (0.17)	$ (0.17)	$ (0.17)	$ (0.62)	$ (0.61)	$ (0.61)

Shares Underlying Stock Options

Shares Underlying Stock Options, Excluded from Calculation of Weighted Average Number of Shares Outstanding used for Calculation of Diluted Net Loss Per Share (Detail) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average number of anti-dilutive potential shares	16,168	13,681	11,722
Stock Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average number of anti-dilutive potential shares	15,592	13,681	11,722
Restricted Stock Units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average number of anti-dilutive potential shares	576

Fair Values on Financial Assets

Fair Values on Financial Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Fair value of financial assets and liabilities
Total financial assets	$ 58,059	$ 96,163
Money market funds
Fair value of financial assets and liabilities
Total financial assets	8,991	59,302
United States government agency securities
Fair value of financial assets and liabilities
Total financial assets	8,029
United States government agency securities | Short-term Investments
Fair value of financial assets and liabilities
Total financial assets	8,029
Corporate debt securities
Fair value of financial assets and liabilities
Total financial assets	37,087	25,698
Marketable equity securities
Fair value of financial assets and liabilities
Total financial assets	3,952	11,163
Level 1
Fair value of financial assets and liabilities
Total financial assets	12,943	70,465
Level 1 | Money market funds
Fair value of financial assets and liabilities
Total financial assets	8,991	59,302
Level 1 | Marketable equity securities
Fair value of financial assets and liabilities
Total financial assets	3,952	11,163
Level 2
Fair value of financial assets and liabilities
Total financial assets	45,116	25,698
Level 2 | United States government agency securities | Short-term Investments
Fair value of financial assets and liabilities
Total financial assets	8,029
Level 2 | Corporate debt securities
Fair value of financial assets and liabilities
Total financial assets	$ 37,087	$ 25,698

Reconciliation of Beginning and

Reconciliation of Beginning and Ending Balances for the Warrant Liability Using Significant Unobservable Inputs (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2015USD ($)
Fair Value Disclosures [Abstract]
Beginning balance	$ 10,485
Increase / (Decrease)in fair value of warrants	(3,566)
Settlement of warrants exercised	(6,919)
Ending balance	$ 0

Fair Value on Financial Instr46

Fair Value on Financial Instruments - Additional Information (Detail)	Dec. 31, 2016shares
Fair Value Disclosures [Abstract]
Class of warrants outstanding	0

Summary of Available-for-Sale S

Summary of Available-for-Sale Securities (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 54,131	$ 85,049
Gross Unrealized Gain	3,952	11,163
Gross Unrealized Loss	(24)	(49)
Fair Value	58,059	96,163
Money market funds
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	8,991	59,302
Fair Value	8,991	59,302
United States government agency securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	8,030
Gross Unrealized Loss	(1)
Fair Value	8,029
Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	37,110	25,747
Gross Unrealized Loss	(23)	(49)
Fair Value	37,087	25,698
Marketable equity securities
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Gain	3,952	11,163
Fair Value	$ 3,952	$ 11,163

Available-for-Sale Debt Securit

Available-for-Sale Debt Securities by Original Contractual Maturity (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Investments Debt And Equity Securities [Abstract]
One year or less, amortized cost	$ 54,131	$ 85,049
Marketable equity securities, amortized cost	0	0
Amortized Cost	54,131	85,049
One year or less, fair value	54,107	85,000
Marketable equity securities, fair value	3,952	11,163
Total available-for-sale securities fair value	$ 58,059	$ 96,163

Available-for-Sale Marketable S

Available-for-Sale Marketable Securities in Unrealized Position (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	$ 40,121	$ 20,170
Less than 12 Months, Unrealized Loss	(24)	(46)
12 Months or Longer, Fair Value		5,528
12 Months or Longer, Unrealized Loss		(3)
Total, Fair Value	40,121	25,698
Total, Unrealized Loss	(24)	(49)
United States government agency securities
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	6,035
Less than 12 Months, Unrealized Loss	(1)
Total, Fair Value	6,035
Total, Unrealized Loss	(1)
Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Less than 12 Months, Fair Value	34,086	20,170
Less than 12 Months, Unrealized Loss	(23)	(46)
12 Months or Longer, Fair Value		5,528
12 Months or Longer, Unrealized Loss		(3)
Total, Fair Value	34,086	25,698
Total, Unrealized Loss	$ (23)	$ (49)

Available-for-Sale Securities -

Available-for-Sale Securities - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Investments Debt And Equity Securities [Abstract]
Other-than-temporary impairment losses	$ 0	$ 0	$ 0
Gross realized gains from the sale of available-for-sale investments	800,000
Gross realized losses from the sale or maturity of available-for-sale investments	$ 0	$ 0	$ 0

Inventories (Detail)

Inventories (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Inventory Disclosure [Abstract]
Work-in-process	$ 5,044	$ 3,187
Finished goods	7,487	7,625
Total inventories	$ 12,531	$ 10,812

Property and Equipment Net (Det

Property and Equipment Net (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	$ 13,272	$ 12,975
Accumulated depreciation and amortization	(10,287)	(9,426)
Total property and equipment, net	2,985	3,549
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	5,678	5,678
Machinery and equipment
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	1,925	1,603
Demonstration equipment
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	167	145
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	871	794
Computer equipment
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	603	591
Computer software
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	2,908	2,935
Consigned equipment
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	1,058	1,010
Construction-in-progress
Property, Plant and Equipment [Line Items]
Total property and equipment, gross	$ 62	$ 219

Property and Equipment Net - Ad

Property and Equipment Net - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Property and equipment, depreciation and amortization expense	$ 1,100,000	$ 1,100,000	$ 700,000
Impairment of long-lived assets	150,000	$ 0	$ 0
Construction-in-progress
Property, Plant and Equipment [Line Items]
Impairment of long-lived assets	$ 200,000

Goodwill and Intangible Assets

Goodwill and Intangible Assets Net - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Goodwill And Intangible Assets Disclosure [Abstract]
Dispose, impair or recognition of additional goodwill	$ 0
Impairment charges on goodwill	0
Impairment losses recognized related to the acquired intangible assets	0	$ 0	$ 0
Annual amortization expense of the intangible assets, 2017	200,000
Annual amortization expense of the intangible assets, 2018	200,000
Annual amortization expense of the intangible assets, 2019	200,000
Annual amortization expense of the intangible assets, 2020	$ 100,000

Summary of Intangible Assets Ne

Summary of Intangible Assets Net (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 2,017	$ 2,017
Accumulated Amortization	(1,279)	(1,077)
Net Carrying Amount	738	940
Reacquired license - INTERCEPT Asia
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	2,017	2,017
Accumulated Amortization	(1,279)	(1,077)
Net Carrying Amount	$ 738	$ 940

Marketable Equity Investments -

Marketable Equity Investments - Additional Information (Detail) - USD ($)	1 Months Ended	12 Months Ended
	Apr. 30, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Investment [Line Items]
Eligibility to receive a royalty fee		1.00%
Royalty income, nonoperating		$ 0	$ 0	$ 0
Carrying value of investment		0
Gain on sale of investment in marketable equity securities		$ 750,000
Common stock, shares outstanding		99,095,000	99,095,000
Aduro
Investment [Line Items]
Preferred shares converted to common stock	396,700
Sale of common stock in marketable equity investment		50,000
Gain on sale of investment in marketable equity securities		$ 800,000
Common stock, shares outstanding		346,700

Accrued Liabilities (Detail)

Accrued Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Payables And Accruals [Abstract]
Accrued compensation and related costs	$ 7,098	$ 5,198
Accrued professional services	2,511	2,337
Accrued customer costs	534	987
Accrued insurance premiums	476	438
Other accrued expenses	599	893
Total accrued liabilities	$ 11,218	$ 9,853

Debt (Detail)

Debt (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Total debt, Principal	$ 19,499
Less: debt-current	(6,934)	$ (2,956)
Debt-non-current	12,441	16,848
Cerus Term Loans
Debt Instrument [Line Items]
Total debt, Principal	19,499	20,000
Total debt, Unamortized Discount	(124)	(196)
Total debt	19,375	19,804
Less: debt - current, Principal	(7,013)	(3,050)
Less: debt - current, Unamortized Discount	79	94
Less: debt-current	(6,934)	(2,956)
Debt - non-current, Principal	12,486	16,950
Debt - non-current, Unamortized Discount	(45)	(102)
Debt-non-current	$ 12,441	$ 16,848

Debt - Principal and Interest P

Debt - Principal and Interest Payments on Debt (Detail) $ in Thousands	Dec. 31, 2016USD ($)
Debt Disclosure [Abstract]
2017, Principal	$ 7,013
2018, Principal	8,178
2019, Principal	4,308
Total, Principal	19,499
2017, Interest	1,160
2018, Interest	613
2019, Interest	1,488
Total, Interest	3,261
2017, Total	8,173
2018, Total	8,791
2019, Total	5,796
Total	$ 22,760

Debt - Additional Information (

Debt - Additional Information (Detail) - Cerus Term Loans	Jun. 30, 2014USD ($)Tranche	Dec. 31, 2016
Line of Credit Facility [Line Items]
Maximum borrowing limit	$ 30,000,000
Term of agreement	5 years
Number of loan tranches | Tranche	3
Interest rate, description		Term Loan A bears an interest rate of 6.95%. Term Loan B bears an interest rate of 7.01%.
Principal and interest payments	36 months	29 months
Final payment term percent	7.00%
Terms of required periodic payments of interest and principal		The Company was required to make interest only payments through June 2016, followed by thirty-six months of equal principal and interest payments thereafter. On July 28, 2016, the Term Loan Agreement was amended to include an additional interest-only period for all advances under the Term Loan Agreement. As amended, the Company is required to make interest only payments from August 2016 through January 2017, followed by twenty-nine months of equal principal and interest payments thereafter. The Company determined that the amendment to the Term Loan Agreement resulted in a modification. As a result, the accounting treatment for the Term Loan will continue under the interest method, with a new effective interest rate based on revised cash flows calculated on a prospective basis upon the execution of the amendment to the Term Loan Agreement. The Company is also required to make a final payment equal to 7% of the principal amounts of the Term Loans drawn payable on the earlier to occur of maturity or prepayment.
First Tranche (Term Loan A)
Line of Credit Facility [Line Items]
Loan and security agreement	$ 10,000,000
Interest rate	6.95%
Maturity period		Jun. 1, 2019
Second Tranche (Term Loan B)
Line of Credit Facility [Line Items]
Loan and security agreement	$ 10,000,000
Borrowing conditions		The second tranche of $10.0 million (“Term Loan B”) was drawn on June 15, 2015.
Interest rate		7.01%
Maturity period		Jun. 1, 2019
Third Tranche (Term Loan C)
Line of Credit Facility [Line Items]
Loan and security agreement	$ 10,000,000
Borrowing conditions		As amended, the availability of Term Loan C was subject to the Company achieving consolidated trailing six months’ revenue at a specified threshold (the “Revenue Event”) no later than June 30, 2016.
Securities Pledged as Collateral
Line of Credit Facility [Line Items]
Percentage of investments made in subsidiary	35.00%

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) $ in Millions	12 Months Ended					15 Months Ended
	Dec. 31, 2016USD ($)€ / Unit	Dec. 31, 2016EUR (€)€ / Unit	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2010USD ($)	Dec. 31, 2016EUR (€)	Dec. 31, 2016EUR (€)
Commitments and Contingencies Disclosure [Line Items]
Minimum term of non-cancellable operating leases	1 year	1 year
Expiration of non-cancellable operating leases maximum year	2,021	2,021
Operating lease, rent expense	$ 0.8		$ 0.8	$ 0.7
Financing for leasehold improvement					$ 1.1
Outstanding liability related to leasehold improvements	0.4
Purchase commitment, paid	6.9		$ 7.7	$ 6.8
Future minimum purchase commitment 2017	6.5
Future minimum purchase commitment 2018	0.6
Future minimum purchase commitment 2019	0.3
Future minimum purchase commitment 2020	0.4
Future minimum purchase commitment 2021	$ 1.7
Transition agreement expiration date	Sep. 30, 2014	Sep. 30, 2014
Distribution fee per disposable kit | € / Unit	10	10
Potential maximum payment of distribution fee | €		€ 3,000,000
Distribution related expense paid	$ 0.5	€ 500,000				€ 900,000
Distribution related expense accrued	0.1						€ 100,000
Accrued liabilities
Commitments and Contingencies Disclosure [Line Items]
Leasehold Improvements reflected in Accrued liabilities	0.1
Other non-current liabilities
Commitments and Contingencies Disclosure [Line Items]
Leasehold Improvements reflected in Other non-current liabilities	$ 0.3

Future Minimum Non-Cancelable L

Future Minimum Non-Cancelable Lease Payments Under Operating Leases (Detail) $ in Thousands	Dec. 31, 2016USD ($)
Commitments And Contingencies Disclosure [Abstract]
2,017	$ 1,233
2,018	868
2,019	739
2,020	30
2,021	2
Total minimum non-cancellable lease payments	$ 2,872

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - USD ($)	1 Months Ended	12 Months Ended
	Nov. 30, 2010	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	May 05, 2016
Stockholders Equity Note [Line Items]
Proceeds from common stock sold		$ 22,121,000	$ 75,300,000	$ 18,488,000
Preferred stock, shares issued		0	0
Class of warrants outstanding		0
2010 Warrants
Stockholders Equity Note [Line Items]
Warrants, number of common stock shares	3,700,000
Warrant exercise price	$ 3.20
Warrants exercisable date	May 15, 2011
Exercisable period	5 years
Class of warrants outstanding		0
Stockholder Rights Plan
Stockholders Equity Note [Line Items]
Minimum percentage of common stock acquired by stockholders		15.00%
Designated preferred stock for future issuance		250,000
Series C Junior Participating preferred stock
Stockholders Equity Note [Line Items]
Preferred stock, shares issued		0
Cantor | Sales Agreement | Amendment No. 2
Stockholders Equity Note [Line Items]
Maximum common stock offering price		$ 132,200,000
Common stock registered for sale		$ 62,300,000			$ 70,000,000
Percentage of proceeds payable as compensation to underwriter		2.00%
Common stock, number of shares issued		3,500,000	0
Proceeds from common stock sold		$ 22,000,000	$ 0

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) $ / shares in Units, $ in Millions	Jun. 10, 2015shares	Dec. 31, 2016USD ($)Period$ / sharesshares	Dec. 31, 2015USD ($)$ / sharesshares	Dec. 31, 2014USD ($)$ / shares	Aug. 31, 2016shares	Jun. 12, 2013shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total intrinsic value of options exercised | $		$ 1.9	$ 1.2	$ 3.8
Stock-based compensation, expected dividend yield		0.00%
Weighted average grant-date fair value of stock options granted | $ / shares		$ 2.55	$ 2.35	$ 3.28
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense expected to be recognized | $		$ 11.2
Stock-based compensation, weighted average recognition period		2 years 4 months 24 days
Stock-based compensation, expected dividend yield		0.00%	0.00%	0.00%
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense expected to be recognized | $		$ 2.6
Stock-based compensation, weighted average recognition period		2 years 2 months 12 days
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation, option to be granted at percentage of fair value of common stock		85.00%
Employee Stock Purchase Plan, offering period		12 months
Number of purchase periods within each offering period | Period		2
Increase in shares of common stock authorized for issuance	1,500,000	1,320,500
Aggregate number of shares of common stock reserved for future issuance		1,438,211
Stock-based compensation, expected dividend yield		0.00%	0.00%	0.00%
Weighted average grant-date fair value of awards granted | $ / shares		$ 1.87	$ 1.54	$ 1.42
2008 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation, option to be granted at percentage of fair value of common stock		100.00%
Increase in shares of common stock authorized for issuance	5,000,000
Aggregate number of shares of common stock reserved for future issuance		21,600,000
Employee Stock Purchase Plan, authorized shares for issuance						19,500,000
Stock-based compensation, award term		10 years
Performance-based stock options, outstanding		0
Outstanding options and other stock based awards		15,787,000	14,119,000
Number of shares available for future issuance		5,100,000
2008 Equity Incentive Plan | Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation, vesting period		4 years
2008 Equity Incentive Plan | Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation, vesting period		3 years
Number of Restricted Stock Units Outstanding		739,000	0
Weighted average grant-date fair value of awards granted | $ / shares		$ 5.26
2008 Equity Incentive Plan | Performance-based Stock or Cash Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee Stock Purchase Plan, authorized shares for issuance		500,000
Stock option plan granted on cash award | $		$ 1
Cerus Corporation Inducement Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate number of shares of common stock reserved for future issuance					1,250,000

Activity Under Equity Incentive

Activity Under Equity Incentive Plans Related to Stock Options (Detail) - 2008 Equity Incentive Plan shares in Thousands	12 Months Ended
	Dec. 31, 2016$ / sharesshares
Activity under the Company's equity incentive plans related to stock options
Number of Options Outstanding, Beginning Balance | shares	14,119
Granted, Number of Options Outstanding | shares	2,722
Forfeited, Number of Options Outstanding | shares	(287)
Expired, Number of Options Outstanding | shares	(128)
Exercised, Number of Options Outstanding | shares	(639)
Number of Options Outstanding, Ending Balance | shares	15,787
Weighted Average Exercise Price per Share
Weighted Average Exercise Price per Share, Beginning Balance | $ / shares	$ 4.21
Granted, Weighted Average Exercise Price per Share | $ / shares	5.39
Forfeited, Weighted Average Exercise Price per Share | $ / shares	4.93
Expired, Weighted Average Exercise Price per Share | $ / shares	9.18
Exercised, Weighted Average Exercise Price per Share | $ / shares	3.45
Weighted Average Exercise Price per Share, Ending Balance | $ / shares	$ 4.39

Activity Under Equity Incenti66

Activity Under Equity Incentive Plans Related to RSUs (Detail) - 2008 Equity Incentive Plan - Restricted Stock Units (RSUs) shares in Thousands	12 Months Ended
	Dec. 31, 2016$ / sharesshares
Activity under the Company's equity incentive plans related to restricted stock units
Number of Restricted Stock Units Outstanding, Beginning Balance | shares	0
Granted, Number of Restricted Stock Units Outstanding | shares	762
Forfeited, Number of Restricted Stock Units Outstanding | shares	(23)
Vested, Number of Restricted Stock Units Outstanding | shares	0
Number of Restricted Stock Units Outstanding, Ending Balance | shares	739
Weighted Average Exercise Price per Share
Weighted Average Exercise Price per Share, Beginning Balance | $ / shares	$ 0
Granted, Weighted Average Exercise Price per Share | $ / shares	5.26
Forfeited, Weighted Average Exercise Price per Share | $ / shares	5.06
Vested, Weighted Average Exercise Price per Share | $ / shares	0
Weighted Average Exercise Price per Share, Ending Balance | $ / shares	$ 5.26

Information Regarding Stock Opt

Information Regarding Stock Options Outstanding Stock Options Vested and Expected to Vest and Stock Options Exercisable (Detail) - 2008 Equity Incentive Plan - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Number of Shares
Outstanding options and other stock based awards	15,787	14,119
Stock options vested and expected to vest	15,541
Stock options exercisable	10,600
Weighted Average Exercise Price
Stock options outstanding	$ 4.39	$ 4.21
Stock options vested and expected to vest	4.38
Stock options exercisable	$ 4.03
Weighted Average Remaining Contractual (Years)
Stock options outstanding	6 years 3 months 18 days
Stock options vested and expected to vest	6 years 2 months 12 days
Stock options exercisable	5 years 3 months 18 days
Aggregate intrinsic value
Stock options outstanding	$ 8,696
Stock options vested and expected to vest	8,695
Stock options exercisable	$ 8,557

Stock-Based Compensation Recogn

Stock-Based Compensation Recognized on Condensed Consolidated Statements of Operations (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 8,065	$ 6,730	$ 5,153
Research and Development Expense
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	1,091	1,260	998
Selling, General and Administrative Expenses
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 6,974	$ 5,470	$ 4,155

Weighted Average Assumptions Us

Weighted Average Assumptions Used to Value Stock-Based Awards (Detail)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation, expected dividend yield	0.00%
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	5 years 10 months 6 days	5 years 7 months 28 days	5 years 8 months 16 days
Estimated volatility	49.00%	56.00%	61.00%
Risk-free interest rate	1.41%	1.55%	1.73%
Stock-based compensation, expected dividend yield	0.00%	0.00%	0.00%
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term (in years)	9 months 4 days	9 months	9 months 4 days
Estimated volatility	47.00%	53.00%	52.00%
Risk-free interest rate	0.55%	0.28%	0.10%
Stock-based compensation, expected dividend yield	0.00%	0.00%	0.00%

Retirement Plan - Additional In

Retirement Plan - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2016
Compensation And Retirement Disclosure [Abstract]
Retirement plan, employees maximum pre-tax contributions percentage	60.00%

Development and License Agree71

Development and License Agreements - Additional Information (Detail) € in Millions	1 Months Ended	12 Months Ended
	Jun. 30, 2016USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2016EUR (€)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2016EUR (€)	Dec. 31, 2015EUR (€)
Licenses Agreements [Line Items]
Royalty payments on products		$ 0		$ 1,900,000	$ 2,500,000
Manufacturing and development obligations - current				3,282,000
Manufacturing and development obligations - non-current		4,770,000		4,542,000
Payments made relating to the manufacturing of the products		16,100,000		14,900,000	$ 19,100,000
Amounts due from Fresenius		$ 300,000		200,000
BARDA Agreement
Licenses Agreements [Line Items]
Committed fund receivable	$ 41,600,000
Committed fund receivable	185,000,000
Period of agreement		5 years	5 years
Accounts receivable		$ 1,000,000		0
Other current assets
Licenses Agreements [Line Items]
Research and development assets		900,000		4,100,000
Other assets
Licenses Agreements [Line Items]
Research and development assets		2,000,000
Manufacturing efficiency assets		2,100,000		2,400,000
Fresenius
Licenses Agreements [Line Items]
Allocated amount for research and development activities		4,800,000
Manufacturing efficiency activity cost		2,400,000
Cerus Corporation | BARDA Agreement
Licenses Agreements [Line Items]
Co-investment by the company	$ 15,000,000
Manufacturing and Supply Agreement
Licenses Agreements [Line Items]
Accrual for manufacturing of entity products		$ 3,000,000		2,500,000
Manufacturing and Supply Agreement | Fresenius
Licenses Agreements [Line Items]
Payments made based on the successful achievement of production volumes | €			€ 8.6
Manufacturing and development obligations, discount rate		9.72%	9.72%
Manufacturing and development payments		$ 3,400,000	€ 3.1
Accrual for manufacturing and development of entity products		$ 4,800,000		$ 7,800,000		€ 4.5	€ 7.2
Manufacturing and development obligations - current | €							3
Manufacturing and development obligations - non-current | €							€ 4.2

United States and Foreign Compo

United States and Foreign Components of Consolidated Loss before Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
U.S.	$ (63,246)	$ (59,897)	$ (38,928)
Foreign	515	358	368
Loss before income taxes	$ (62,731)	$ (59,539)	$ (38,560)

Provision Benefit for Income Ta

Provision Benefit for Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Foreign	$ 147	$ 147	$ 168
Federal	0	0	0
State			1
Total current	147	147	169
Foreign	0	0	0
Federal	28	(3,750)	22
State		(68)	4
Total deferred	28	(3,818)	26
Provision (benefit) for income taxes	$ 175	$ (3,671)	$ 195

Difference Between Provision fo

Difference Between Provision for Income Taxes and Amounts Computed by Applying Federal Statutory Income Tax Rate to Loss before Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Federal statutory tax	$ (21,329)	$ (20,243)	$ (13,110)
Warrants		(3,565)	(3,367)
Expiration of federal loss carryovers		3,337
Change in valuation allowance	13,589	11,754	16,576
Change in state apportionment		4,085
Revision to prior year items	7,551
Other	364	961	96
Provision (benefit) for income taxes	$ 175	$ (3,671)	$ 195

Significant Components of Defer

Significant Components of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Deferred tax assets:
Net operating loss carryforwards	$ 176,490	$ 165,813
Research and development credit carryforwards	31,777	35,131
Capitalized research and development	22,575	17,916
Deferred compensation	8,242	5,908
Other	3,184	3,911
Total deferred tax assets	242,268	228,679
Valuation allowance	(238,443)	(224,854)
Net deferred tax assets	3,825	3,825
Deferred tax liabilities:
Unrealized gain on investments	3,825	3,825
Amortization of goodwill	150	122
Total deferred tax liabilities	$ 3,975	$ 3,947

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Line Items]
Increase in valuation allowance	$ 13,600	$ 11,800	$ 14,100
Loss before income taxes	(62,731)	(59,539)	$ (38,560)
Operating loss carryforwards related to windfall tax deductions	2,800
Research and development tax credit carryforwards	31,777	$ 35,131
Internal Revenue Service (IRS)
Income Tax Disclosure [Line Items]
Net operating loss carryforwards	503,000
Research and development tax credit carryforwards	$ 23,900
Internal Revenue Service (IRS) | Minimum
Income Tax Disclosure [Line Items]
Net operating loss carryforwards, expiration year	2,017
Research and development tax credit carryforwards, expiration year	2,018
Internal Revenue Service (IRS) | Maximum
Income Tax Disclosure [Line Items]
Net operating loss carryforwards, expiration year	2,036
Research and development tax credit carryforwards, expiration year	2,036
California Franchise Tax Board | Latest Tax Year
Income Tax Disclosure [Line Items]
Tax year remain subject to examination by the taxing jurisdictions	1,998
California Franchise Tax Board | Latest Tax Year
Income Tax Disclosure [Line Items]
Tax year remain subject to examination by the taxing jurisdictions	2,015
Tax and Customs Administration, Netherlands | Latest Tax Year
Income Tax Disclosure [Line Items]
Tax year remain subject to examination by the taxing jurisdictions	2,013
Tax and Customs Administration, Netherlands | Latest Tax Year
Income Tax Disclosure [Line Items]
Tax year remain subject to examination by the taxing jurisdictions	2,015
State and Local Jurisdiction
Income Tax Disclosure [Line Items]
Net operating loss carryforwards	$ 94,000
Research and development tax credit carryforwards	$ 11,900
State and Local Jurisdiction | Minimum
Income Tax Disclosure [Line Items]
Net operating loss carryforwards, expiration year	2,017
State and Local Jurisdiction | Maximum
Income Tax Disclosure [Line Items]
Net operating loss carryforwards, expiration year	2,036
Domestic Tax Authority | Latest Tax Year
Income Tax Disclosure [Line Items]
Tax year remain subject to examination by the taxing jurisdictions	1,998
Domestic Tax Authority | Latest Tax Year
Income Tax Disclosure [Line Items]
Tax year remain subject to examination by the taxing jurisdictions	2,015
Cerus Europe B.V.
Income Tax Disclosure [Line Items]
Undistributed earning of foreign subsidiary	$ 5,200
Unrecognized deferred tax liability for unrepatriated earnings	$ 1,900

Reconciliation of Unrecognized

Reconciliation of Unrecognized Tax Benefits (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)
Income Tax Disclosure [Abstract]
Unrecognized tax benefits at beginning of period	$ 0
Increases related to prior year tax positions	10,691
Increases related to current year tax positions	145
Unrecognized tax benefits at beginning of period	$ 10,836

Segment, Customer and Geograp78

Segment, Customer and Geographic Information - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2016Segment
Segment Reporting [Abstract]
Number of operating segments	1

Significant Customer that Accou

Significant Customer that Accounted for More than Ten Percentage of Total Product Revenue (Detail) - Customer Concentration Risk - Sales Revenue, Goods, Net	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Advanced Technology Company KSC
Revenue, Major Customer [Line Items]
Concentration risk, percentage	12.00%
Etablissement Francais du Sang
Revenue, Major Customer [Line Items]
Concentration risk, percentage		23.00%	25.00%

Revenue by Geographical Locatio

Revenue by Geographical Location (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenue, Major Customer [Line Items]
Product revenue	$ 10,125	$ 10,175	$ 9,251	$ 7,632	$ 9,656	$ 8,045	$ 8,830	$ 7,692	$ 37,183	$ 34,223	$ 36,416
Government contracts revenue	$ 1,831	$ 261							2,092
Total revenue									39,275	34,223	36,416
BELGIUM
Revenue, Major Customer [Line Items]
Product revenue									6,392	5,728	4,456
UNITED STATES
Revenue, Major Customer [Line Items]
Product revenue									4,480	563	350
Government contracts revenue									2,092
KUWAIT
Revenue, Major Customer [Line Items]
Product revenue									4,415	1,959	2,557
FRANCE
Revenue, Major Customer [Line Items]
Product revenue									3,485	7,732	9,184
SPAIN
Revenue, Major Customer [Line Items]
Product revenue									3,360	4,070	2,776
SWITZERLAND
Revenue, Major Customer [Line Items]
Product revenue									3,324	2,938	3,784
CIS
Revenue, Major Customer [Line Items]
Product revenue									2,859	3,361	6,636
Other Countries
Revenue, Major Customer [Line Items]
Product revenue									$ 8,868	$ 7,872	$ 6,673

Long Lived Assets by Geographic

Long Lived Assets by Geographical Location (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Long-Lived Assets by Geographical Areas [Line Items]
Total long-lived assets	$ 3,723	$ 4,489
U.S. And Territories
Long-Lived Assets by Geographical Areas [Line Items]
Total long-lived assets	3,529	4,260
Europe And Other
Long-Lived Assets by Geographical Areas [Line Items]
Total long-lived assets	$ 194	$ 229

Summary of Quarterly Financial

Summary of Quarterly Financial Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Product revenue	$ 10,125	$ 10,175	$ 9,251	$ 7,632	$ 9,656	$ 8,045	$ 8,830	$ 7,692	$ 37,183	$ 34,223	$ 36,416
Gross profit on product revenue	4,520	4,724	4,275	3,369	3,494	2,485	1,802	2,978	16,888	10,759	15,228
Government contracts revenue	1,831	261							2,092
Net loss	$ (13,501)	$ (14,376)	$ (18,166)	$ (16,863)	$ (14,756)	$ (15,680)	$ (15,972)	$ (9,460)	$ (62,906)	$ (55,868)	$ (38,755)
Basic	$ (0.13)	$ (0.14)	$ (0.18)	$ (0.17)	$ (0.15)	$ (0.16)	$ (0.17)	$ (0.10)	$ (0.62)	$ (0.58)	$ (0.52)
Diluted	$ (0.13)	$ (0.14)	$ (0.18)	$ (0.17)	$ (0.15)	$ (0.17)	$ (0.17)	$ (0.17)	$ (0.62)	$ (0.61)	$ (0.61)