Portola Pharmaceuticals (PTLA) 10-Q 6 May 16 2016 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2016	Apr. 29, 2016
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q1
Trading Symbol	PTLA
Entity Registrant Name	PORTOLA PHARMACEUTICALS INC
Entity Central Index Key	1,269,021
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		56,469,995

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands		Mar. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	[1]	$ 210,704	$ 186,488
Short-term investments	[1]	210,275	257,713
Restricted cash (Development Partner)	[1]	262	341
Receivables from collaborators	[1]	7,500	1,000
Prepaid research and development	[1]	10,854	16,976
Prepaid expenses and other current assets	[1]	3,295	3,059
Total current assets	[1]	442,890	465,577
Property and equipment, net	[1]	6,779	6,243
Intangible asset	[1]	3,151	3,151
Long-term investments	[1]		15,960
Prepaid and other long-term assets	[1]	11,177	11,993
Total assets	[1]	463,997	502,924
Current liabilities:
Accounts payable	[1]	13,281	10,279
Accrued compensation and employee benefits	[1]	2,709	5,459
Accrued research and development	[1]	17,574	24,195
Accrued and other liabilities	[1]	2,725	2,826
Deferred revenue, current portion	[1]	16,938	8,387
Total current liabilities	[1]	53,227	51,146
Deferred revenue, long-term	[1]	34,570	18,629
Other long-term liabilities	[1]	2,660	2,826
Total liabilities	[1]	$ 90,457	$ 72,601
Stockholders’ equity:
Preferred stock, $0.001 par value, 5,000,000 shares authorized; no shares issued and outstanding	[1]
Common stock, $0.001 par value, 100,000,000 shares authorized at March 31, 2016 and December 31, 2015; 56,469,789 and 56,359,515 shares issued and outstanding at March 31, 2016 and December 31, 2015, respectively	[1]	$ 57	$ 57
Additional paid-in capital	[1]	1,084,766	1,076,791
Accumulated deficit	[1]	(714,276)	(649,302)
Accumulated other comprehensive income/(loss)	[1]	66	(150)
Total stockholders’ equity	[1]	370,613	427,396
Noncontrolling interest (Development Partner)	[1]	2,927	2,927
Total stockholders' equity	[1]	373,540	430,323
Total liabilities and stockholders’ equity	[1]	$ 463,997	$ 502,924
[1]	Amounts include the assets and liabilities of our Development Partner a consolidated variable interest entity (“VIE”). Portola's interests and obligations with respect to the VIE's assets and liabilities are limited to those accorded to Portola in its agreement with the VIE. See Note 7, “Asset Acquisition and License Agreements,” to these condensed consolidated financial statements.

Condensed Consolidated Balance3

Condensed Consolidated Balance Sheets (Parenthetical) (Unaudited) - $ / shares	Mar. 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	100,000,000	100,000,000
Common stock, shares issued	56,469,789	56,359,515
Common stock, shares outstanding	56,469,789	56,359,515

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Income Statement [Abstract]
Collaboration and license revenue	$ 8,258	$ 2,359
Operating expenses:
Research and development	58,813	39,858
Selling, general and administrative	14,751	9,005
Total operating expenses	73,564	48,863
Loss from operations	(65,306)	(46,504)
Interest and other income (expense), net	332	(409)
Net loss	(64,974)	(46,913)
Net loss attributable to Portola	$ (64,974)	$ (46,913)
Net loss per share attributable to Portola common stockholders:
Basic and diluted	$ (1.15)	$ (0.95)
Shares used to compute net loss per share attributable to Portola common stockholders:
Basic and diluted	56,397,881	49,527,850

Condensed Consolidated Stateme5

Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (64,974)	$ (46,913)
Other comprehensive income:
Unrealized gain on available-for-sale securities, net of tax	216	169
Comprehensive loss	(64,758)	(46,744)
Total comprehensive loss attributable to Portola	$ (64,758)	$ (46,744)

Condensed Consolidated Stateme6

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016		Mar. 31, 2015
Operating activities
Net loss	$ (64,974)		$ (46,913)
Adjustments to reconcile net loss to cash used in operating activities:
Depreciation and amortization	457		389
Amortization of premium on investment securities	474		932
Stock-based compensation expense	7,069		5,172
Changes in operating assets and liabilities:
Receivables from collaborators			45
Prepaid research and development	6,122		(7,076)
Prepaid expenses and other current assets	(236)		798
Prepaid and other long-term assets	816		934
Accounts payable	3,344		(8,827)
Accrued compensation and employee benefits	(2,750)		(1,754)
Accrued research and development	(6,621)
Accrued and other liabilities	137		10,420
Deferred revenue	17,992		(2,358)
Other long-term liabilities	(166)		1,093
Net cash used in operating activities	(38,336)		(47,145)
Investing activities
Purchases of property and equipment	(1,335)		(1,063)
Decrease in restricted cash (Development Partner)	79
Purchases of investments	(52,544)		(90,940)
Proceeds from maturities of investments	115,684		101,439
Net cash provided by investing activities	61,884		9,436
Financing activities
Proceeds from public offering of common stock, net of underwriters discount			108,772
Payment of public offering cost	(242)
Proceeds from issuance of common stock pursuant to equity award plans	910		4,269
Net cash provided by financing activities	668		113,041
Net increase in cash and cash equivalents	24,216		75,332
Cash and cash equivalents at beginning of period	186,488	[1]	57,514
Cash and cash equivalents at end of period	$ 210,704	[1]	$ 132,846
[1]	Amounts include the assets and liabilities of our Development Partner a consolidated variable interest entity (“VIE”). Portola's interests and obligations with respect to the VIE's assets and liabilities are limited to those accorded to Portola in its agreement with the VIE. See Note 7, “Asset Acquisition and License Agreements,” to these condensed consolidated financial statements.

Organization

Organization	3 Months Ended
	Mar. 31, 2016
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Organization	1. Organization Portola Pharmaceuticals, Inc. ® Our two late stage development programs address significant unmet medical needs in the area of thrombosis, or blood clots. Our lead compound, betrixaban, is a U.S. Food and Drug Administration, or FDA, designated Fast-Track novel oral once-daily inhibitor of Factor Xa. Our second compound, andexanet alfa, an FDA-designated breakthrough therapy and orphan drug, is a recombinant protein designed to reverse anticoagulant activity in patients treated with a Factor Xa inhibitor. Our third compound, cerdulatinib, is being developed for hematologic, or blood, cancers and inflammatory disorders. Cerdulatinib is an orally available dual kinase inhibitor that inhibits spleen tyrosine kinase, or Syk, and janus kinases, or JAK, enzymes that regulate important signaling pathways. We also have an early stage program of highly selective Syk inhibitors, one of which is partnered with Ora, Inc., or Ora.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2016
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Consolidation and Basis of Presentation The accompanying unaudited condensed consolidated financial statements include the amounts of Portola and its wholly-owned subsidiaries and a Development Partner that is a variable interest entity (a “VIE”) for which Portola is deemed, under applicable accounting guidance, to be the primary beneficiary as of March 31, 2016. The unaudited condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”), and follow the requirements of the Securities and Exchange Commission (“SEC”) for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by U.S. GAAP can be condensed or omitted. These condensed consolidated financial statements have been prepared on the same basis as our annual consolidated financial statements and, in the opinion of management, reflect all adjustments, consisting only of normal recurring adjustments that are necessary for a fair statement of our financial information. The results of operations for the three months ended March 31, 2016 are not necessarily indicative of the results to be expected for the year ending December 31, 2016 or for any other interim period or for any other future year. The condensed consolidated balance sheet as of December 31, 2015 has been derived from audited financial statements at that date but does not include all of the information required by U.S. GAAP for complete financial statements. The accompanying condensed consolidated financial statements and related financial information should be read in conjunction with the audited financial statements and the related notes thereto for the year ended December 31, 2015 included in our Annual Report on Form 10-K filed February 29, 2016 with the SEC. Use of Estimates The preparation of condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent liabilities and the reported amounts of revenues and expenses in the condensed consolidated financial statements and the accompanying notes. On an ongoing basis, management evaluates its estimates, including those related to revenue recognition, clinical trial accruals, fair value of assets and liabilities, income taxes, in-process research and development, the consolidation of VIEs and deconsolidation of VIEs and stock-based compensation. Management bases its estimates on historical experience and on various other market-specific and relevant assumptions that management believes to be reasonable under the circumstances. Actual results may differ from those estimates. Variable Interest Entities We review agreements we enter into with third party entities, pursuant to which we may have a variable interest in that entity, in order to determine if the entity is a VIE. If the entity is a VIE, we assess whether or not we are the primary beneficiary of that entity. In determining whether we are the primary beneficiary of an entity, we apply a qualitative approach that determines whether we have both (1) the power to direct the economically significant activities of the entity and (2) the obligation to absorb losses of, or the right to receive benefits from, the entity that could potentially be significant to that entity. If we determine we are the primary beneficiary of a VIE, we consolidate the operations and financial position of the VIE into our consolidated financial statements. Our determination about whether we should consolidate such VIEs is made continuously as changes to existing relationships or future transactions may result in a consolidation or deconsolidation event. In-process Research and Development Asset In-process research and development asset relates to our consolidated VIE and are considered to be indefinite-lived until the completion or abandonment of the associated research and development efforts which generally occurs if and when regulatory approval to market a product is obtained, Cash and Cash Equivalents Cash and cash equivalents consist of cash and other highly liquid investments with original maturities of three months or less from the date of purchase. Investments in Marketable Securities All investments in marketable securities have been classified as “available-for-sale” and are carried at estimated fair value as determined based upon quoted market prices or pricing models for similar securities. Management determines the appropriate classification of our investments in debt securities at the time of purchase and reevaluates such designation as of each balance sheet date. Unrealized gains and losses are excluded from earnings and were reported as a component of accumulated comprehensive income (loss). Realized gains and losses and declines in fair value judged to be other than temporary, if any, on available-for-sale securities are included in interest and other income, net. The cost of securities sold is based on the specific-identification method. Interest on marketable securities is included in interest and other income, net. Collaboration Collaboration customers who accounted for 10% or more of total collaboration and license revenues were as follows: Three Months Ended March 31, 2016 2015 Daiichi Sankyo, Inc. 41 % 48 % Bayer Pharma, AG and Janssen Pharmaceuticals, Inc. 40 % 34 % Bristol-Myers Squibb Company and Pfizer Inc. 15 % 16 % Revenue Recognition We generate revenue from collaboration and license agreements for the development and commercialization of our products. Collaboration and license agreements may include non-refundable or partially refundable upfront license fees, partial or complete reimbursement of research and development costs, contingent consideration payments based on the achievement of defined collaboration objectives and royalties on sales of commercialized products. Our performance obligations under our collaborations may include the transfer of intellectual property rights (licenses), obligations to provide research and development services and related clinical drug supply, obligations to provide regulatory approval services and obligations to participate on certain development and/or commercialization committees with the collaborators. If we determine that multiple deliverables exist, the consideration is allocated to one or more units of accounting based upon the best estimate of the selling price of each deliverable. The selling price used for each deliverable will be based on vendor-specific objective evidence, if available, third-party evidence if vendor-specific objective evidence is not available, or estimated selling price if neither vendor-specific or third-party evidence is available. Payments that are contingent upon achievement of a substantive milestone are recognized in their entirety in the period in which the milestone is achieved. A milestone is defined as an event that can only be achieved based on our performance and there is substantive uncertainty about whether the event will be achieved at the inception of the arrangement. Events that are contingent only on the passage of time or only on counterparty performance are not considered milestones subject to this guidance. Further, the amounts received must relate solely to prior performance, be reasonable relative to all of the deliverables and payment terms within the agreement and commensurate with our performance to achieve the milestone after commencement of the agreement. Payments contingent upon achievement of events that are not considered substantive milestones are allocated to the respective arrangements unit of accounting when received and recognized as revenue based on the revenue recognition policy for that unit of accounting. Amounts received from our collaboration and license agreements are recognized as revenue if the collaboration arrangement involves the sale of services associated with the development and commercialization of our products at amounts that exceed our cost. Under certain collaboration arrangements we receive reimbursement for a portion of our research and development costs. Such funding is recognized as a reduction in research and development expense when we engage in a research and development project jointly with another entity, with both entities participating in project activities and sharing costs and potential benefits of the arrangement. Amounts related to research and development and regulatory approval funding are recognized as the related services or activities are performed, in accordance with the contract terms. Payments may be made to or by us based on the number of full-time equivalent researchers assigned to the collaboration project and the related research and development expenses incurred. Net Loss per Share Attributable to Portola Common Stockholders Basic net loss per share attributable to Portola Common Stockholders is calculated by dividing the net loss attributable to Portola Common Stockholders by the weighted-average number of shares of Common Stock outstanding for the period. Diluted net loss per share attributable to Portola Common Stockholders is computed by giving effect to all potential dilutive Common Stock equivalents outstanding for the period. Diluted net loss per share attributable to Portola Common Stockholders is the same as basic net loss per share attributable to Portola Common Stockholders, since the effects of potentially dilutive securities are antidilutive. Recent Accounting Pronouncements In April 2016, the Financial Accounting Standards Board (the "FASB") issued ASU 2016-10, Identifying Performance Obligations and Licensing In March 2016, the FASB issued ASU No. 2016-09, Improvements to Employee Share-Based Payment Accounting In March 2016, the FASB issued ASU No. 2016-08, Principal versus Agent Considerations (Reporting Revenue Gross versus Net). In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842). In April 2015, the FASB issued ASU 2015-05, Goodwill and Other - Internal-Use Software. In February 2015, the FASB issued ASU 2015-02, Consolidation: amendment to the consolidation analysis

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2016
Fair Value Disclosures [Abstract]
Fair Value Measurements	3. Fair Value Measurements Financial assets and liabilities are recorded at fair value. The carrying amounts of certain of our financial instruments, including cash and cash equivalents, restricted cash, short-term investments, receivables from collaborations, prepaid research and development, prepaid expenses and other current assets and accounts payable, accrued research and development, accrued compensation and employee benefits, accrued and other liabilities and deferred revenue, approximate their fair value due to their short maturities. The accounting guidance for fair value provides a framework for measuring fair value, clarifies the definition of fair value, and expands disclosures regarding fair value measurements. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability (an exit price) in an orderly transaction between market participants at the reporting date. The accounting guidance establishes a three-tiered hierarchy, which prioritizes the inputs used in the valuation methodologies in measuring fair value as follows: Level 1 – Inputs are unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date. Level 2 – Inputs (other than quoted market prices included in Level 1) are either directly or indirectly observable for the asset or liability through correlation with market data at the measurement date and for the duration of the instrument’s anticipated life. Level 3 – Inputs reflect management’s best estimate of what market participants would use in pricing the asset or liability at the measurement date. Consideration is given to the risk inherent in the valuation technique and the risk inherent in the inputs to the model. In certain cases where there is limited activity or less transparency around inputs to valuation, securities are classified as Level 3. The following table sets forth the fair value of our financial assets and liabilities, allocated into Level 1, Level 2 and Level 3, that were measured on a recurring basis (in thousands): March 31, 2016 Level 1 Level 2 Level 3 Total Financial Assets: Money market funds $ 29,876 $ — $ — $ 29,876 Corporate notes and commercial paper — 217,971 — 217,971 U.S. government agency securities — 127,605 — 127,605 Total financial assets $ 29,876 $ 345,576 $ — $ 375,452 December 31, 2015 Level 1 Level 2 Level 3 Total Financial Assets: Money market funds $ 22,074 $ — $ — $ 22,074 Corporate notes and commercial paper — 242,033 — 242,033 U.S. government agency securities — 180,876 — 180,876 Total financial assets $ 22,074 $ 422,909 $ — $ 444,983 We estimate the fair values of our corporate notes and commercial paper and U.S government agency securities by taking into consideration valuations obtained from third-party pricing services. The pricing services utilize industry standard valuation models, including both income- and market-based approaches, for which all significant inputs are observable, either directly or indirectly, to estimate fair value. These inputs include reported trades of and broker/dealer quotes on the same or similar securities; issuer credit spreads; benchmark securities; prepayment/default projections based on historical data; and other observable inputs. There were no transfers between Level 1 and Level 2 during the periods presented.

Financial Instruments

Financial Instruments	3 Months Ended
	Mar. 31, 2016
Investments Debt And Equity Securities [Abstract]
Financial Instruments	4. Financial Instruments Cash equivalents and investments, all of which are classified as available-for-sale securities, consisted of the following (in thousands): March 31, 2016 December 31, 2015 Estimated Estimated Unrealized Unrealized Fair Unrealized Unrealized Fair Cost Gain (Loss) Value Cost Gain (Loss) Value Money market funds $ 29,876 $ — $ — $ 29,876 $ 22,074 $ — $ — $ 22,074 Corporate notes and commercial paper 217,955 19 (3 ) 217,971 242,089 3 (59 ) 242,033 U.S. government agency securities 127,555 57 (7 ) 127,605 180,970 1 (95 ) 180,876 $ 375,386 $ 76 $ (10 ) $ 375,452 $ 445,133 $ 4 $ (154 ) $ 444,983 Classified as: Cash equivalents $ 165,177 $ 171,310 Short-term investments 210,275 257,713 Long-term investments — 15,960 Total cash equivalents and investments $ 375,452 $ 444,983 At March 31, 2016, the remaining contractual maturities of available-for-sale securities were less than one year and at December 31, 2015 the remaining contractual maturities of available-for-sale securities were less than two years. There have been no significant realized gains or losses on available-for-sale securities for the periods presented.

Collaboration and License Agree

Collaboration and License Agreements	3 Months Ended
	Mar. 31, 2016
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Collaboration and License Agreements	5. Collaboration and License Agreements Summary of Collaboration-Related Revenue We have recognized revenue from our collaboration and license agreements as follows (in thousands): Three Months Ended March 31, 2016 2015 Daiichi Sankyo $ 3,385 $ 1,128 Bayer and Janssen 3,307 799 BMS and Pfizer 1,254 380 Bayer 260 — Lee ’ 52 52 Total collaboration and license revenue $ 8,258 $ 2,359 Daiichi Sankyo, Inc. (“Daiichi Sankyo”) In June 2013, we entered into an agreement with Daiichi Sankyo to include subjects dosed with edoxaban, their Factor Xa inhibitor product, in one of our Phase 2 proof-of-concept studies of andexanet alfa. We are responsible for the cost of conducting this clinical study. Under the terms of the agreement, Daiichi Sankyo provided us with an upfront fee of $6.0 million, $3.0 million of which was subject to refund if Daiichi Sankyo decided to terminate the agreement. We are obligated to participate in a Joint Collaboration Committee (“JCC”) with Daiichi Sankyo to oversee the collaboration activities under the agreement. We identified the following performance deliverables under the agreement: 1) the obligation to provide research and development services, which includes supplying andexanet alfa and providing a final written report, and 2) the obligation to participate in the JCC. We considered the provisions of the multiple-element arrangement guidance and accounted for the research and development services and our participation in the JCC as a single unit of accounting. We originally estimated the non-contingent consideration under this agreement of $3.0 million would be recorded as revenue on a straight-line basis over the estimated non-contingent performance period through the second quarter of 2014. In December 2013, the JCC agreed to forego certain preclinical studies that were planned in the original study design at the inception of the agreement. As a result of this change, we updated our non-contingent performance period to be through the first quarter of 2014. The recognition of contingent consideration under this agreement of $3.0 million commenced upon resolution of the contingency in the first quarter of 2014 and was recognized through the fourth quarter of 2015. During the three months ended March 31, 2015, we recognized $258,000, in collaboration revenue associated with the contingent and non-contingent elements of this arrangement. There was no deferred revenue balance under this agreement as of March 31, 2016. In July 2014, we entered into an agreement with Daiichi Sankyo to study the safety and efficacy of andexanet alfa as a reversal agent to their oral Factor Xa inhibitor, edoxaban, in our Phase 3 and Phase 4 studies. We are responsible for the cost of conducting these clinical studies. Pursuant to our agreement with Daiichi Sankyo we are obligated to provide research, development and regulatory services and to participate in a JCC in exchange for an upfront nonrefundable fee of $15.0 million, up to two contingent payments totaling $5.0 million which are payable upon the initiation of our Phase 3 study and achievement of certain events associated with scaling up our manufacturing process to support a commercial launch, and up to four payments totaling $20.0 million which are payable upon acceptance of filing and regulatory approval of andexanet alfa as a reversal agent to edoxaban by the FDA and EMA. We identified the following non-cancellable performance deliverables under the agreement: 1) the obligation to provide research and development services, which include manufacturing and supplying andexanet alfa and providing various reports, 2) the obligation to provide regulatory approval services, and 3) the obligation to participate in the JCC. We considered the provisions of the multiple-element arrangement guidance and determined that none of the deliverables had standalone value, all of these obligations will be delivered throughout the estimated period of performance and will be accounted as a single unit of accounting. The total upfront consideration under this agreement is being recognized as revenue on a straight-line basis over the estimated performance period through the third quarter of 2018. We have determined all but one of the future contingent payments meet the definition of a milestone and that such milestones are substantive in that the consideration is reasonable relative to all of the deliverables and the payment terms within the agreement are commensurate with our performance to achieve the milestone after commencement of the agreement. Accordingly, revenue for the achievement of these milestones will be recognized in the period when the milestone is achieved and collectability is reasonably assured. For the three months ended March 31, 2016, we recognized $2.5 million in collaboration revenue associated with achievement of a milestone. As of March 31, 2015, no amounts had been recognized as collaboration revenue for any of these milestones. Amounts for the contingent payment not considered to be a substantive milestone will be deferred when received and recognized as collaboration revenue on a straight-line basis over the remaining performance period. All remaining contingent payments remained eligible for achievement as of March 31, 2016. During the three months ended March 31, 2016 and 2015, we recognized $3.4 million and $871,000 in collaboration revenue under this agreement, respectively. The deferred revenue balance under this agreement as of March 31, 2016 was $8.8 million. In March 2016, we entered into an agreement with Daiichi Sankyo to perform an ethnic sensitivity study (“ESS-Study”) of Japanese ethnicity and to deliver services, in connection with our collaboration agreement to commercialize andexanet alfa in Japan with BMS and Pfizer, related to further studies as requested by the Japanese regulatory authorities to obtain final regulatory approval and to have commercialized andexanet alfa as a reversal agent to edoxaban in Japan. Daiichi Sankyo will reimburse us for 33% of our costs and expenses incurred to conduct the ESS-Study and between 33% and 100% of costs and expenses we incur for other studies that involve edoxaban under the terms of the arrangement. Pursuant to our agreement with Daiichi Sankyo, we are obligated to provide research and development services, clinical drug supply and related manufacturing services, regulatory approval services and to participate in a JCC in exchange for an upfront nonrefundable fee of $5.0 million. We are eligible to receive, up to two contingent payments totaling $10.0 million which are payable upon the initial and final regulatory approval for andexanet alfa as a reversal agent to edoxaban in Japan. The $10.0 million contingent payments will be reduced to $7.0 million if the Japanese regulatory approval is attained based only upon the ESS-study results. We concluded that the July 2014 and March 2016 agreements should each be accounted for as standalone agreements. We identified the following non-cancellable performance deliverables under the March 2016 agreement: 1) the obligation to provide research and development services 2) the obligation to provide regulatory approval services, 3) the obligation to manufacture and provide clinical supply of andexanet alfa, and 4) the obligation to participate in the JCC. We considered the provisions of the multiple-element arrangement guidance and determined that none of the deliverables have standalone value and accordingly will be accounted for as a single unit of accounting. The total upfront consideration received under this agreement is being recognized as revenue on a straight-line basis over the estimated performance period associated with our participation in the JCC through the first quarter of 2019. We have determined that the future contingent payments meet the definition of a milestone and that such milestones are substantive in that the consideration is reasonable relative to all of the deliverable and payment term within the agreement are commensurate with our performance to achieve the milestones after commencement of the agreement. Accordingly, revenue for the achievement of these milestones will be recognized in the period when the milestones are achieved and collectability is reasonably assured. As of March 31, 2016, no amounts had been recognized as collaboration revenue for any of these milestones and the contingent payments remain eligible for achievement as of March 31, 2016. During the three months ended March 31, 2016 we recognized $5,000 in collaboration revenue under this agreement. The deferred revenue balance under this agreement as of March 31, 2016 was $5.0 million. Bayer Pharma, AG (“Bayer”) and Janssen Pharmaceuticals, Inc. (“Janssen”) In February 2013, we entered into a three-way agreement with Bayer and Janssen to include subjects dosed with rivaroxaban, their Factor Xa inhibitor product, in one of our Phase 2 proof-of-concept studies of andexanet alfa. We are responsible for the cost of conducting this clinical study. Under the terms of the agreement, Bayer and Janssen have each provided us with an upfront and non-refundable fee of $2.5 million, for an aggregate fee of $5.0 million. The agreement also provides for additional non-refundable payments to us from Bayer and Janssen of $250,000 each for an aggregate of $500,000 following the delivery of the final written study report of our Phase 2 proof-of-concept studies of andexanet alfa. Also, we are obligated to participate on a JCC with Bayer and Janssen to oversee the collaboration activities under the agreement. We identified the following performance deliverables under the agreement: 1) the obligation to provide research and development services, which includes supplying andexanet alfa and providing a final written report, and 2) the obligation to participate in a JCC. We considered the provisions of the multiple-element arrangement guidance and determined that that none of the deliverables had standalone value and therefore they were accounted for as a single unit of accounting. The total upfront consideration under this agreement was recognized as revenue on a straight-line basis over the estimated performance period through the fourth quarter of 2014 and $500,000 was recognized in the third quarter of 2015 following the delivery of the final written study report of our Phase 2 proof-of-concept studies of andexanet alfa. In January 2014, we entered into a three-way agreement with Bayer and Janssen to study the safety and efficacy of andexanet alfa as a reversal agent to their oral Factor Xa inhibitor, rivaroxaban, in our Phase 3 studies. We are responsible for the cost of conducting this clinical study. Pursuant to our agreement with Bayer and Janssen we are obligated to provide research, development and regulatory services and to participate in a JCC in exchange for an upfront nonrefundable fee of $10.0 million. We are also eligible to receive, up to three contingent payments totaling $7.0 million which are payable upon achievement of certain events associated with scaling up our manufacturing process to support a commercial launch, and up to three payments totaling $8.0 million which are payable upon initiation of our Phase 3 study and regulatory approval of andexanet alfa as a reversal agent to rivaroxaban by the FDA and European Medicines Agency (“EMA”). We identified the following non-cancellable performance deliverables under the agreement: 1) the obligation to provide research and development services, which include manufacturing and supplying andexanet alfa and providing various reports, 2) the obligation to provide regulatory approval services, and 3) the obligation to participate in the JCC. We considered the provisions of the multiple-element arrangement guidance and determined that none of the deliverables have standalone value; all of these obligations will be delivered throughout the estimated period of performance and accounted for as a single unit of accounting. The total upfront consideration under this agreement is being recognized as revenue on a straight-line basis over the estimated period of performance period. In the third quarter of 2014 we updated our estimated period of performance from the first quarter of 2017 to the first quarter of 2018 to reflect a modification to our clinical development and regulatory plans. We have determined all but one of the future contingent payments meet the definition of a milestone and that such milestones are substantive in that the consideration is reasonable relative to all of the deliverables and the payment terms within the agreement and commensurate with our performance to achieve the milestone after commencement of the agreement. Accordingly, revenue for the achievement of these milestones will be recognized in the period when the milestone is achieved and collectability is reasonably assured. For the three months ended March 31, 2016, we recognized $ 2.5 million in collaboration revenue associated with achievement of a milestone. As of March 31, 2015, no amounts had been recognized as collaboration revenue for any of these milestones. The contingent payment of $3.0 million, not considered to be a substantive milestone, was received in the third quarter of 2014 and is being recognized as collaboration revenue on a straight-line basis over the estimated performance period through the first quarter of 2018. All remaining contingent payments remained eligible for achievement as of March 31, 2016. During the three months ended March 31, 2016 and 2015, we recognized $3.3 million and $799,000 in collaboration revenue under this agreement, respectively. The deferred revenue balance under this agreement as of March 31, 2016 was $6.5 million. Bayer Pharma, AG (“Bayer”) In February 2016, we entered into an agreement with Bayer to perform an ESS-Study of Japanese ethnicity and to deliver services, in connection with our collaboration agreement to commercialize andexanet alfa in Japan with BMS and Pfizer, related to any further studies as requested by the Japanese regulatory authorities to obtain final regulatory approval and to have commercialized andexanet alfa as a reversal agent to rivaroxaban in Japan. Bayer will reimburse us 33% of our costs and expenses incurred to conduct the ESS-Study and between 33% and 100% of costs and expenses we incur for other studies that involve rivaroxaban under the terms of the arrangement. Pursuant to our agreement with Bayer we are obligated to provide research and development services, provide clinical drug supply and related manufacturing services, provide regulatory approval services and to participate in a JCC in exchange for an upfront nonrefundable fee of $5.0 million. We are also eligible to receive, one contingent payment of $10.0 million which is payable upon the initial regulatory approval for andexanet alfa for rivaroxaban in Japan. The $10.0 million contingent payment will be reduced to $7.0 million if Japanese regulatory approval is attained based only upon the ESS-study results. We concluded that the January 2014 agreement with Bayer and Janssen and February 2016 agreement with Bayer should each be accounted for as standalone agreements. We identified the following non-cancellable performance deliverables under the February 2016 agreement: 1) the obligation to provide research and development services 2) the obligation to provide regulatory approval services, 3) the obligation to manufacture and provide clinical supply of andexanet alfa, and 4) the obligation to participate in the JCC. We considered the provisions of the multiple-element arrangement guidance and determined that none of the deliverables had standalone value, all of these obligations will be delivered throughout the estimated period of performance and accounted for as a single unit of accounting. The total upfront consideration under this agreement is being recognized as revenue on a straight-line basis over the estimated performance period through the first quarter of 2019. We have determined that the future contingent payment meets the definition of a milestone and that such milestone is substantive in that the consideration is reasonable relative to all of the deliverables and payment terms within the agreement are commensurate with our performance to achieve the milestone after commencement of the agreement. Accordingly, revenue for the achievement of the milestone will be recognized in the period when the milestone is achieved and collectability is reasonably assured. As of March 31, 2016, no amounts had been recognized as collaboration revenue for any of this milestone and the contingent payment remains eligible for achievement as of March 31, 2016. During the three months ended March 31, 2016 we recognized $260,000 in collaboration revenue under this agreement. The deferred revenue balance under this agreement as of March 31, 2016 was $4.7 million. Bristol-Myers Squibb Company (“BMS”) and Pfizer Inc. (“Pfizer”) In January 2014, we entered into a collaboration agreement with BMS and Pfizer to further study andexanet alfa as a reversal agent for their jointly owned FDA approved oral Factor Xa inhibitor, apixaban, through Phase 3 studies. We initiated Phase 3 studies in the first half of 2014. We are responsible for the cost of conducting this clinical study. Pursuant to our agreement with BMS and Pfizer we are obligated to provide research, development and regulatory approval services and participate in the JCC in exchange for a partially refundable upfront fee of $13.0 million and up to $12.0 million of contingent milestone payments due upon achievement of certain development and regulatory events. All consideration received and to be earned under this agreement is subject to a 50% refund contingent upon certain regulatory and/or clinical events. We identified the following non-cancellable performance deliverables under the January 2014 agreement: 1) the obligation to provide research and development services, which include manufacturing and supplying andexanet alfa and providing various reports, 2) the obligation to provide regulatory approval services, and 3) the obligation to participate in the JCC. We considered the provisions of the multiple-elements arrangement guidance and determined that none of the deliverables have standalone value, all of these obligations will be delivered throughout the estimated period of performance and accounted for as a single unit of accounting. The non-contingent upfront consideration under this agreement of $6.5 million is being recognized on a straight-line basis over the estimated period of performance. In the third quarter of 2014, we revised the remaining estimated period of performance from the first quarter of 2017 to the first quarter of 2018 to reflect a modification to our clinical development and regulatory plans. The contingent upfront consideration of $6.5 million will be recognized if and when the refundable nature of these amounts lapses based upon the achievement of specified regulatory and/or clinical events. The contingent milestone payments under the January 2014 agreement are not considered substantive because a portion may be refunded upon certain events. The non-contingent portion of the milestone payment will be recognized as collaboration revenue on a straight-line basis over the estimated period of performance, which is now through the first quarter of 2018. The contingent portion of the milestone payments will be recognized if and when the refundable nature of these amounts lapses based upon the achievement of specified regulatory and/or clinical events. For the three months ended March 31, 2016, we received two contingent milestone payments totaling $2.8 million and $750,000 remains payable to us related to the achievement of one of these milestones. The non-contingent portion of these milestones is being recognized in collaboration revenue on a straight-line basis over the estimated remaining period of performance and the contingent portion of these milestones are included in deferred revenue, long term in the condensed consolidated balance sheet. Two of the contingent payments totaling $4.0 million remain eligible for achievement as of March 31, 2016. During the three months ended March 31, 2016 and 2015, we recognized $475,000 and $380,000 in collaboration revenue under this agreement, respectively. The deferred revenue balance under this agreement as of March 31, 2016 was $12.2 million. In February 2016, we entered into a collaboration and license agreement with BMS and Pfizer whereby BMS and Pfizer obtained exclusive rights to develop and commercialize andexanet alfa in Japan. BMS and Pfizer are responsible for all development, regulatory and commercial activities in Japan and we will reimburse BMS and Pfizer for expenses they incur for research and development activities specific to Factor Xa inhibitors other than apixaban. Pursuant to this agreement, we are obligated to provide certain research and development activities outside of Japan, provide clinical drug supply and related manufacturing services and to participate on various committees in exchange for a non-refundable upfront fee of $15.0 million. We are also eligible to receive, contingent payments totaling up to $20.0 million which may be earned upon achievement of certain regulatory events and up to $70.0 million which may be earned upon achievement of specified annual net sales volumes in Japan. We are also entitled to receive royalties ranging from 5%-15% on net sales of andexanet alfa in Japan. We concluded that the January 2014 and February 2016 agreements should each be accounted for as standalone agreements. We identified the following non-cancellable performance deliverables under the February 2016 agreement: 1) grant of intellectual property license, 2) the obligation to provide research and development services, 3) the obligation to manufacture and provide clinical supply of andexanet alfa, and 4) the obligation to participate in various committees. The February 2016 agreement also contains an obligation to manufacture and provide commercial supply of andexanet alfa which we concluded was a contingent deliverable because andexanet alfa is not yet a commercially approved product. We considered the provisions of the multiple-elements arrangement guidance and determined that none of the deliverables have standalone value because of our required expertise associated with the manufacturing process of andexanet alfa and the interdependency of the remaining deliverables on the clinical supply of andexanet alfa. We evaluated the timing of delivery for each of the deliverables and concluded that our obligation to participate on the various committees would be the last delivered element under the arrangement and therefore would be the basis for revenue recognition for the combined unit of accounting. The total upfront consideration under this agreement is being recognized as revenue on a straight-line basis over the estimated performance period through the first quarter of 2019. We have determined that the future contingent payments meet the definition of a milestone and that such milestones are substantive in that the consideration is reasonable relative to all of the deliverables and payment terms within the agreement are commensurate with our performance to achieve the milestone after commencement of the agreement. Accordingly, revenue for the achievement of the milestone will be recognized in the period when the milestone is achieved and collectability is reasonably assured. As of March 31, 2016, no amounts had been recognized as collaboration revenue for any of these milestones and all the contingent payments remain eligible for achievement as of March 31, 2016. During the three months ended March 31, 2016 we recognized $779,000 in collaboration revenue under this agreement. The deferred revenue balance under this agreement as of March 31, 2016 was $14.2 million. Lee’s Pharmaceutical (HK) Ltd (“Lee’s”) In January 2013, we entered into an agreement with Lee’s to jointly expand our Phase 3 APEX Study of betrixaban into China. Under the terms of the agreement, Lee’s provided us with an upfront and non-refundable fee of $700,000 and will reimburse our costs in connection with the expansion of our APEX study into China. Lee’s will lead this study and the regulatory interactions with China’s State Food and Drug Administration. We granted Lee’s an exclusive option to negotiate for the exclusive commercial rights to betrixaban in China, which may be exercised by Lee’s for 60 days after it receives the primary data analysis report from the Phase 3 APEX study. We identified the following deliverables under the agreement with Lee’s: 1) the granting of an exclusive option to negotiate for the exclusive commercial rights to betrixaban in China, 2) the obligation to manufacture and supply product in support of the APEX study in China, 3) the obligation to participate in a joint working group, and 4) the delivery of the primary data analysis report from our APEX study. We considered the provisions of the multiple-element arrangement guidance and determined that none of the deliverables have standalone value and therefore are accounted for as a single unit of accounting with the upfront fee recognized as revenue on a straight-line basis over the estimated period of performance. Any reimbursements we may receive from Lee’s for the costs we incur in connection with this agreement have not been material. During the three months ended March 31, 2016 and 2015, we recognized $52, 000 and $52,000 in collaboration revenue under this agreement, respectively. The deferred revenue balance under this agreement as of March 31, 2016 and 2015was $0 and $200,000, respectively. Ora, Inc. (“Ora”) In May 2015, we entered into a license and collaboration agreement with Ora pursuant to which we granted Ora an exclusive license to co-develop and co-commercialize one of our specific Syk inhibitors, PRT2761. Ora has the primary responsibility for conducting the research and development and regulatory activities under this agreement. We are obligated to provide assistance in accordance with the agreed- upon development plan as well as participate on various committees. Under the terms of this risk and cost sharing agreement, each party will incur its own share of development costs. Third-party related development costs will be shared by Ora and us at approximately 60% and 40%, respectively, until an End of Phase 2 meeting with the FDA, and equally thereafter. We are entitled to receive either 50% of the profits, if any, generated by future sales of the products developed under the agreement or royalty payments on such sales, should we opt out of the agreement. We may opt out of the agreement any time prior to 90 days after an End of Phase 2 meeting with the FDA. The timing of the exercise of our opt out rights would impact future royalties we would be entitled to receive from Ora. Each party may also buy out the rights and interests in the licensed compound by paying the greater of $6.0 million or two times the actual aggregate development cost incurred by both parties before or 90 days after an End of Phase 2 meeting with the FDA. All costs we incur in connection with this agreement will be recognized as research and development expenses. During the three months ended March 31, 2016, we incurred $351,000 of costs related to this agreement. Biogen Idec, Inc. (“Biogen Idec”) In October 2011, we entered into an exclusive, worldwide license and collaboration agreement with Biogen Idec to develop and commercialize selective, novel oral Syk inhibitors for the treatment of autoimmune and inflammatory diseases. In November 2012, we exercised our option to convert the agreement to a fully out-licensed agreement. After the election, we relinquished our right to share profits from sales of products related to PRT2607 and other selective Syk inhibitors, but were entitled to receive future payments up to approximately $370.0 million based on the occurrence of certain development and regulatory events for all licensed compounds. In April 2014, we entered into an amendment to the Biogen Idec license and collaboration agreement under which Biogen Idec released one of the Syk kinase inhibitors to us and we would be required to pay Biogen Idec $15.0 million upon the completion of certain commercial milestones and pay royalties on sales of products approved for the Syk inhibitor. In May 2015, our agreement with Biogen Idec terminated in its entirety effective July 2015. The effect of termination resulted in return to us of all compounds subject to the license and collaboration agreement and eliminated all potential future payments from and to Biogen Idec. We did not record any reduction to research and development expense pursuant to the agreement for the three months ended March 31, 2016 and 2015, respectively.

Commercial Supply Agreement

Commercial Supply Agreement	3 Months Ended
	Mar. 31, 2016
Commitments And Contingencies Disclosure [Abstract]
Commercial Supply Agreement	6. Commercial Supply Agreement In July 2014, we entered into an agreement with CMC ICOS Biologics, Inc. (“CMC Biologics”), a subsidiary of CMC Biologics S.à.r.l., a privately-held contract manufacturing organization, pursuant to which CMC Biologics will manufacture clinical and commercial supply of andexanet alfa. Under the agreement, we are required to purchase an aggregate fixed number of batches of andexanet alfa from CMC Biologics beginning in 2015 through 2021. Total batch commitments under the agreement can be increased or decreased based on the achievement of milestones relating to the regulatory approval process for andexanet alfa, expansion of existing manufacturing capacity and operational qualification of CMC Biologics’ manufacturing facilities. We made an upfront payment to CMC Biologics in the amount of $10.0 million in July 2014 and a reservation payment to CMC Biologics of $4.6 million in November 2014. Both payments will be credited against our future purchases of batches under the agreement. Total fixed commitments under the agreement for the purchases of clinical and commercial batches, not taking into account possible price and batch adjustments per the terms of the agreement, are approximately $276.1 million. Payments made for purchases of batches since inception of this agreement as of March 31, 2016 amount to $40.7 million. The term of the agreement is seven years and may be early terminated by either party for the other party’s uncured material breach or insolvency. We may also terminate the agreement if CMC Biologics is unable to add additional manufacturing capacity on a timely basis, if certain manufacturing-related regulatory events do not occur before certain deadlines, or if the batch yield is below a certain threshold, in which case we are not obligated to pay CMC Biologics a termination payment and CMC Biologics will be obligated to refund the uncredited amounts of the upfront payment and reservation payment. In addition, we may terminate the agreement unilaterally if we discontinue the development and commercialization of andexanet alfa for regulatory, safety, efficacy or other commercial reasons, or if the projected market demand or gross margin of andexanet alfa is below a minimum threshold. The termination provisions will obligate us to pay CMC Biologics a termination fee between $5.0 million and $30.0 million, depending on the date of termination. The termination fee is highest from 2015 through 2017, and then decreases through 2021. Any remaining upfront payments or reservation payments we have made, not yet credited against the purchase of batches, at the time of termination will be applied against the termination fee. Under the consolidation guidance, we determined that CMC Biologics is and continues to be a VIE, but that we are not CMC Biologics’ primary beneficiary and therefore consolidation of CMC Biologics by us is not required. As of March 31, 2016, we have not provided financial, or other, support to CMC Biologics that was not previously contractually required. The upfront and reservation payment of $14.6 million is recorded as $10.6 million in prepaid and other long-term assets and $2.8 million in prepaid research and development in the condensed consolidated balance sheet, net of amortization as of March 31, 2016. The unamortized payments made for purchases of batches of $7.7 million are recorded in prepaid research and development in the condensed consolidated balance sheet as of March 31, 2016. These assets represent our maximum exposure to loss under this agreement at March 31, 2016. The upfront payment will be charged to research and development expense, prior to regulatory approval of andexanet alfa, as services are rendered or batches are delivered. Also, we have recorded an accrual for services rendered by CMC Biologics of $857,000 in accrued research and development in the condensed consolidated balance sheet as of March 31, 2016. We are currently not able to quantify the exposure to losses associated with the fixed pricing terms of this agreement.

Asset Acquisition and License A

Asset Acquisition and License Agreements	3 Months Ended
	Mar. 31, 2016
Research And Development [Abstract]
Asset Acquisition and License Agreements	7. Asset Acquisition and License Agreements Agreement with Early Development Stage Company (“Development Partner”) In December 2015, we entered into an agreement with an early development stage limited liability company to explore a novel approach to develop a drug in the field of hypercholesterolemia. We plan to advance the program in collaboration with the Development Partner through an agreed-upon development plan and are obligated to fund the development effort over the initial term of the arrangement expected to be through August 2016. We determined that the Development Partner is and continues to be a variable interest entity and that we hold a variable interest in the Development Partner’s intellectual property assets and the related potential future product candidates these assets may produce. Due to the absence of other significant development programs at the Development Partner, we concluded that the variable interest was in the entity as a whole and not the intellectual property assets. Given the stage of development, we continued to conclude that Development Partner was considered not to be a business as they lacked the processes required to generate outputs. As we are primarily funding and have the power to unilaterally amend the development plan during the initial term and thus control those activities most significant to the Development Partner, we are considered to be the primary beneficiary of the Development Partner. Accordingly, the Development Partner is subject to consolidation and we have consolidated the financial statements of the Development Partner since inception of the agreement on December 1, 2015 by (a) eliminating all intercompany balances and transactions; (b) allocating loss attributable to the noncontrolling interest in the Development Partner to net loss attributable to noncontrolling interest in our consolidated statement of operations and reflecting noncontrolling interest on our consolidated balance sheet. Our interest in the Development Partner is limited to the development of the intellectual property asset. The upfront payment of $500,000 and the obligation to fund the development plan represent our maximum exposure to loss under the agreement. At the inception of the agreement, the identifiable assets, assumed liabilities and non-controlling interest of the Development Partner were recorded at their estimated fair value upon the initial consolidation of the Development Partner, including the in-process research and development intangible asset. We estimated the fair value of this indefinite lived intangible assets to be $3.2 million and the noncontrolling interest to be $2.9 million. The fair value was estimated using present-value models on potential contingent milestones and royalty payments, based on assumptions regarding the probability of achieving the development milestones, estimate of time to develop the drug candidate, estimates of future cash flows from potential product sales and assumptions regarding the appropriate discount rate. As of March 31, 2016, we have not provided financial or other support to the Development Partner that was not previously contracted or required. We recorded the Development Partner’s $262,000 of cash as restricted cash because (a) we do not have any interest in or control over Development Partner's cash and (b) the agreement does not provide for these assets to be used for the development of the intellectual property assets developed pursuant to this agreement. Also, as we are funding the development effort since inception of the arrangement, we have not allocated any net loss to the noncontrolling interest.

Stock Based Compensation

Stock Based Compensation	3 Months Ended
	Mar. 31, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock Based Compensation	8. Stock Based Compensation In January 2013, our Board of Directors adopted our 2013 Equity Incentive Plan, or the 2013 Plan, which became effective upon of the closing of our initial public offering in May 2013. On January 1, 2016, the number of shares available for issuance under the 2013 Plan automatically increased by a number of shares equal to 5% of the total common stock outstanding at December 31, 2015. As of March 31, 2016 there were 12,205,425 shares reserved under the 2013 Plan for the future issuance of equity awards. Stock Options The following table summarizes stock option activity under our 2013 Plan and related information: Shares Subject Weighted- Outstanding Average Exercise Options Price Per Share Balance at December 31, 2015 4,731,483 $ 24.19 Options granted 980,215 $ 32.51 Options exercised (10,984 ) $ 15.52 Options canceled (85,230 ) $ 28.85 Balance at March 31, 2016 5,615,484 $ 25.59 The estimated grant date fair values of the employee stock options were calculated using the Black Scholes valuation model, based on the following assumptions: For the Three Months Ended March 31, 2016 2015 Risk-free interest rate 1.61 % 1.54 % Expected life 6.0 years 6.0 years Expected volatility 64 % 66 % Dividend yield — — Restricted stock units (“RSUs”) In January 2015, the Compensation Committee of our Board of Directors approved the commencement of granting restricted stock units, to our employees. RSUs are share awards that entitle the holder to receive freely tradable shares of our Common Stock upon vesting. The following table summarizes RSU activity, under our 2013 Plan and related information: Shares Subject to Weighted- Outstanding Average grant date RSUs fair value per share Balance at December 31, 2015 167,750 $ 30.86 RSUs granted 215,655 $ 33.49 RSUs released (55,195 ) $ 30.88 RSUs canceled (9,982 ) $ 31.67 Balance at March 31, 2016 318,228 $ 32.62 Performance stock units In January 2015, the Compensation Committee of our Board of Directors approved the commencement of granting performance stock units, to our employees. PSUs are share awards that entitle the holder to receive freely tradable shares of our Common Stock upon achievement of specified conditions. In January 2016, the Compensation Committee of our Board of Directors approved a program to award up to 102,906 PSUs to the management team based on the achievement of certain commercial and regulatory goals related to andexanet alfa and betrixaban, respectively. At March 31, 2016 the achievement of such performance conditions was not deemed probable and therefore no expense has been recognized pursuant to these awards for the three months ended March 31, 2016. The following table summarizes PSU activity, under our 2013 Plan and related information: Shares Subject to Weighted- Outstanding Average grant date PSU's fair value per share Balance at December 31, 2015 205,261 $ 29.33 PSUs granted 102,906 33.49 PSUs released (13,170 ) 50.00 PSUs canceled (1,303 ) 49.44 Balance at March 31, 2016 293,694 29.77 The table below sets forth the functional classification of stock-based compensation expense, net of estimated forfeitures, for the periods presented (in thousands): For the Three Months Ended March 31, 2016 2015 Research and development $ 3,030 $ 2,209 Selling, general and administrative 4,039 2,963 Total stock-based compensation $ 7,069 $ 5,172

Net Loss per Share Attributable

Net Loss per Share Attributable to Common Stockholders	3 Months Ended
	Mar. 31, 2016
Earnings Per Share [Abstract]
Net Loss per Share Attributable to Common Stockholders	9. Net Loss per Share Attributable to Common Stockholders Basic net loss per share attributable to Common Stockholders has been computed by dividing the net loss by the weighted-average number of shares of Common Stock outstanding during the period. Diluted net loss per share attributable to Common Stockholders is calculated by dividing net loss by the weighted average number of shares of Common Stock and potential dilutive securities outstanding during the period. The following common stock equivalent shares were excluded from the computation of diluted net loss per share attributable to Common Stockholders for the periods presented because including them would have been anti-dilutive: Three Months Ended March 31, 2016 2015 Stock options to purchase Common Stock 5,615,484 4,787,869 Common stock warrants 1,500 1,500 Restricted stock units 318,228 171,787 Performance stock units 293,694 140,000

Subsequent Event

Subsequent Event	3 Months Ended
	Mar. 31, 2016
Subsequent Events [Abstract]
Subsequent Event	10. Subsequent Events Betrixaban manufacturing agreement In April 2016, we entered into a Manufacturing Agreement (“the Agreement”) with Hovione, Limited, (“Hovione”), pursuant to which Hovione will manufacture active pharmaceutical ingredient (“API”) for betrixaban at commercial scale and perform process validation during the term of the agreement. Pursuant to the Agreement, we have non-cancellable purchase commitments of $6.0 million and up to $34.0 million of additional payments throughout the term of the Agreement ending June 2018. The additional payments can be cancelled with notice being provided by dates indicated in the Agreement. Further, if the regulatory approval timeline for betrixaban is delayed for regulatory reasons, there is no cancellation right, however the timing of manufacturing and payments under the Agreement will be adjusted up to one year to align with the new regulatory approval timeline. Equity awards In May 2016, we granted equity awards to all employees hired prior to March 1, 2016. These awards consisted of 510,593 stock options, of which 271,122 were granted to the management team and included performance conditions associated with achievement of regulatory and manufacturing milestones through 2018. We also granted 255,301 RSUs to all employees that will vest annually over three years.

Summary of Significant Accoun17

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2016
Accounting Policies [Abstract]
Consolidation and Basis of Presentation	Consolidation and Basis of Presentation The accompanying unaudited condensed consolidated financial statements include the amounts of Portola and its wholly-owned subsidiaries and a Development Partner that is a variable interest entity (a “VIE”) for which Portola is deemed, under applicable accounting guidance, to be the primary beneficiary as of March 31, 2016. The unaudited condensed consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”), and follow the requirements of the Securities and Exchange Commission (“SEC”) for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by U.S. GAAP can be condensed or omitted. These condensed consolidated financial statements have been prepared on the same basis as our annual consolidated financial statements and, in the opinion of management, reflect all adjustments, consisting only of normal recurring adjustments that are necessary for a fair statement of our financial information. The results of operations for the three months ended March 31, 2016 are not necessarily indicative of the results to be expected for the year ending December 31, 2016 or for any other interim period or for any other future year. The condensed consolidated balance sheet as of December 31, 2015 has been derived from audited financial statements at that date but does not include all of the information required by U.S. GAAP for complete financial statements. The accompanying condensed consolidated financial statements and related financial information should be read in conjunction with the audited financial statements and the related notes thereto for the year ended December 31, 2015 included in our Annual Report on Form 10-K filed February 29, 2016 with the SEC.
Use of Estimates	Use of Estimates The preparation of condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent liabilities and the reported amounts of revenues and expenses in the condensed consolidated financial statements and the accompanying notes. On an ongoing basis, management evaluates its estimates, including those related to revenue recognition, clinical trial accruals, fair value of assets and liabilities, income taxes, in-process research and development, the consolidation of VIEs and deconsolidation of VIEs and stock-based compensation. Management bases its estimates on historical experience and on various other market-specific and relevant assumptions that management believes to be reasonable under the circumstances. Actual results may differ from those estimates.
Variable Interest Entities	Variable Interest Entities We review agreements we enter into with third party entities, pursuant to which we may have a variable interest in that entity, in order to determine if the entity is a VIE. If the entity is a VIE, we assess whether or not we are the primary beneficiary of that entity. In determining whether we are the primary beneficiary of an entity, we apply a qualitative approach that determines whether we have both (1) the power to direct the economically significant activities of the entity and (2) the obligation to absorb losses of, or the right to receive benefits from, the entity that could potentially be significant to that entity. If we determine we are the primary beneficiary of a VIE, we consolidate the operations and financial position of the VIE into our consolidated financial statements. Our determination about whether we should consolidate such VIEs is made continuously as changes to existing relationships or future transactions may result in a consolidation or deconsolidation event.
In-process Research and Development Asset	In-process Research and Development Asset In-process research and development asset relates to our consolidated VIE and are considered to be indefinite-lived until the completion or abandonment of the associated research and development efforts which generally occurs if and when regulatory approval to market a product is obtained,
Cash and Cash Equivalents	Cash and Cash Equivalents Cash and cash equivalents consist of cash and other highly liquid investments with original maturities of three months or less from the date of purchase.
Investments in Marketable Securities	Investments in Marketable Securities All investments in marketable securities have been classified as “available-for-sale” and are carried at estimated fair value as determined based upon quoted market prices or pricing models for similar securities. Management determines the appropriate classification of our investments in debt securities at the time of purchase and reevaluates such designation as of each balance sheet date. Unrealized gains and losses are excluded from earnings and were reported as a component of accumulated comprehensive income (loss). Realized gains and losses and declines in fair value judged to be other than temporary, if any, on available-for-sale securities are included in interest and other income, net. The cost of securities sold is based on the specific-identification method. Interest on marketable securities is included in interest and other income, net.
Collaboration Customer Concentration	Collaboration Collaboration customers who accounted for 10% or more of total collaboration and license revenues were as follows: Three Months Ended March 31, 2016 2015 Daiichi Sankyo, Inc. 41 % 48 % Bayer Pharma, AG and Janssen Pharmaceuticals, Inc. 40 % 34 % Bristol-Myers Squibb Company and Pfizer Inc. 15 % 16 %
Revenue Recognition	Revenue Recognition We generate revenue from collaboration and license agreements for the development and commercialization of our products. Collaboration and license agreements may include non-refundable or partially refundable upfront license fees, partial or complete reimbursement of research and development costs, contingent consideration payments based on the achievement of defined collaboration objectives and royalties on sales of commercialized products. Our performance obligations under our collaborations may include the transfer of intellectual property rights (licenses), obligations to provide research and development services and related clinical drug supply, obligations to provide regulatory approval services and obligations to participate on certain development and/or commercialization committees with the collaborators. If we determine that multiple deliverables exist, the consideration is allocated to one or more units of accounting based upon the best estimate of the selling price of each deliverable. The selling price used for each deliverable will be based on vendor-specific objective evidence, if available, third-party evidence if vendor-specific objective evidence is not available, or estimated selling price if neither vendor-specific or third-party evidence is available. Payments that are contingent upon achievement of a substantive milestone are recognized in their entirety in the period in which the milestone is achieved. A milestone is defined as an event that can only be achieved based on our performance and there is substantive uncertainty about whether the event will be achieved at the inception of the arrangement. Events that are contingent only on the passage of time or only on counterparty performance are not considered milestones subject to this guidance. Further, the amounts received must relate solely to prior performance, be reasonable relative to all of the deliverables and payment terms within the agreement and commensurate with our performance to achieve the milestone after commencement of the agreement. Payments contingent upon achievement of events that are not considered substantive milestones are allocated to the respective arrangements unit of accounting when received and recognized as revenue based on the revenue recognition policy for that unit of accounting. Amounts received from our collaboration and license agreements are recognized as revenue if the collaboration arrangement involves the sale of services associated with the development and commercialization of our products at amounts that exceed our cost. Under certain collaboration arrangements we receive reimbursement for a portion of our research and development costs. Such funding is recognized as a reduction in research and development expense when we engage in a research and development project jointly with another entity, with both entities participating in project activities and sharing costs and potential benefits of the arrangement. Amounts related to research and development and regulatory approval funding are recognized as the related services or activities are performed, in accordance with the contract terms. Payments may be made to or by us based on the number of full-time equivalent researchers assigned to the collaboration project and the related research and development expenses incurred.
Net Loss per Share Attributable to Portola Common Stockholders	Net Loss per Share Attributable to Portola Common Stockholders Basic net loss per share attributable to Portola Common Stockholders is calculated by dividing the net loss attributable to Portola Common Stockholders by the weighted-average number of shares of Common Stock outstanding for the period. Diluted net loss per share attributable to Portola Common Stockholders is computed by giving effect to all potential dilutive Common Stock equivalents outstanding for the period. Diluted net loss per share attributable to Portola Common Stockholders is the same as basic net loss per share attributable to Portola Common Stockholders, since the effects of potentially dilutive securities are antidilutive.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In April 2016, the Financial Accounting Standards Board (the "FASB") issued ASU 2016-10, Identifying Performance Obligations and Licensing In March 2016, the FASB issued ASU No. 2016-09, Improvements to Employee Share-Based Payment Accounting In March 2016, the FASB issued ASU No. 2016-08, Principal versus Agent Considerations (Reporting Revenue Gross versus Net). In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842). In April 2015, the FASB issued ASU 2015-05, Goodwill and Other - Internal-Use Software. In February 2015, the FASB issued ASU 2015-02, Consolidation: amendment to the consolidation analysis

Summary of Significant Accoun18

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2016
Accounting Policies [Abstract]
Percentage of Revenue from Significant Collaboration Customers	Collaboration customers who accounted for 10% or more of total collaboration and license revenues were as follows: Three Months Ended March 31, 2016 2015 Daiichi Sankyo, Inc. 41 % 48 % Bayer Pharma, AG and Janssen Pharmaceuticals, Inc. 40 % 34 % Bristol-Myers Squibb Company and Pfizer Inc. 15 % 16 %

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2016
Fair Value Disclosures [Abstract]
Fair Value of Financial Assets and Liabilities Measured on Recurring Basis	The following table sets forth the fair value of our financial assets and liabilities, allocated into Level 1, Level 2 and Level 3, that were measured on a recurring basis (in thousands): March 31, 2016 Level 1 Level 2 Level 3 Total Financial Assets: Money market funds $ 29,876 $ — $ — $ 29,876 Corporate notes and commercial paper — 217,971 — 217,971 U.S. government agency securities — 127,605 — 127,605 Total financial assets $ 29,876 $ 345,576 $ — $ 375,452 December 31, 2015 Level 1 Level 2 Level 3 Total Financial Assets: Money market funds $ 22,074 $ — $ — $ 22,074 Corporate notes and commercial paper — 242,033 — 242,033 U.S. government agency securities — 180,876 — 180,876 Total financial assets $ 22,074 $ 422,909 $ — $ 444,983

Financial Instruments (Tables)

Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2016
Investments Debt And Equity Securities [Abstract]
Cash Equivalents and Investments Classified as Available-for-sale Securities	Cash equivalents and investments, all of which are classified as available-for-sale securities, consisted of the following (in thousands): March 31, 2016 December 31, 2015 Estimated Estimated Unrealized Unrealized Fair Unrealized Unrealized Fair Cost Gain (Loss) Value Cost Gain (Loss) Value Money market funds $ 29,876 $ — $ — $ 29,876 $ 22,074 $ — $ — $ 22,074 Corporate notes and commercial paper 217,955 19 (3 ) 217,971 242,089 3 (59 ) 242,033 U.S. government agency securities 127,555 57 (7 ) 127,605 180,970 1 (95 ) 180,876 $ 375,386 $ 76 $ (10 ) $ 375,452 $ 445,133 $ 4 $ (154 ) $ 444,983 Classified as: Cash equivalents $ 165,177 $ 171,310 Short-term investments 210,275 257,713 Long-term investments — 15,960 Total cash equivalents and investments $ 375,452 $ 444,983

Collaboration and License Agr21

Collaboration and License Agreements (Tables)	3 Months Ended
	Mar. 31, 2016
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Summary of Revenue from Collaboration and License Agreements	We have recognized revenue from our collaboration and license agreements as follows (in thousands): Three Months Ended March 31, 2016 2015 Daiichi Sankyo $ 3,385 $ 1,128 Bayer and Janssen 3,307 799 BMS and Pfizer 1,254 380 Bayer 260 — Lee ’ 52 52 Total collaboration and license revenue $ 8,258 $ 2,359

Stock Based Compensation (Table

Stock Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Stock Option Activity	Stock Options The following table summarizes stock option activity under our 2013 Plan and related information: Shares Subject Weighted- Outstanding Average Exercise Options Price Per Share Balance at December 31, 2015 4,731,483 $ 24.19 Options granted 980,215 $ 32.51 Options exercised (10,984 ) $ 15.52 Options canceled (85,230 ) $ 28.85 Balance at March 31, 2016 5,615,484 $ 25.59 The estimated grant date fair values of the employee stock options were calculated using the Black Scholes valuation model, based on the following assumptions: For the Three Months Ended March 31, 2016 2015 Risk-free interest rate 1.61 % 1.54 % Expected life 6.0 years 6.0 years Expected volatility 64 % 66 % Dividend yield — —
Fair Values of Employee Stock Options	The estimated grant date fair values of the employee stock options were calculated using the Black Scholes valuation model, based on the following assumptions: For the Three Months Ended March 31, 2016 2015 Risk-free interest rate 1.61 % 1.54 % Expected life 6.0 years 6.0 years Expected volatility 64 % 66 % Dividend yield — —
Summary of RSU Activity	The following table summarizes RSU activity, under our 2013 Plan and related information: Shares Subject to Weighted- Outstanding Average grant date RSUs fair value per share Balance at December 31, 2015 167,750 $ 30.86 RSUs granted 215,655 $ 33.49 RSUs released (55,195 ) $ 30.88 RSUs canceled (9,982 ) $ 31.67 Balance at March 31, 2016 318,228 $ 32.62
Summary of PSU Activity	The following table summarizes PSU activity, under our 2013 Plan and related information: Shares Subject to Weighted- Outstanding Average grant date PSU's fair value per share Balance at December 31, 2015 205,261 $ 29.33 PSUs granted 102,906 33.49 PSUs released (13,170 ) 50.00 PSUs canceled (1,303 ) 49.44 Balance at March 31, 2016 293,694 29.77
Classification of Stock-Based Compensation Expense	The table below sets forth the functional classification of stock-based compensation expense, net of estimated forfeitures, for the periods presented (in thousands): For the Three Months Ended March 31, 2016 2015 Research and development $ 3,030 $ 2,209 Selling, general and administrative 4,039 2,963 Total stock-based compensation $ 7,069 $ 5,172

Net Loss per Share Attributab23

Net Loss per Share Attributable to Common Stockholders (Tables)	3 Months Ended
	Mar. 31, 2016
Earnings Per Share [Abstract]
Common Stock Equivalent Shares Excluded from Computation of Diluted Net Loss	The following common stock equivalent shares were excluded from the computation of diluted net loss per share attributable to Common Stockholders for the periods presented because including them would have been anti-dilutive: Three Months Ended March 31, 2016 2015 Stock options to purchase Common Stock 5,615,484 4,787,869 Common stock warrants 1,500 1,500 Restricted stock units 318,228 171,787 Performance stock units 293,694 140,000

Organization - Additional Infor

Organization - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2016Segment
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Number of operating segment	1

Revenue Accounted for 10% or Mo

Revenue Accounted for 10% or More of Total Collaboration and License Revenues (Detail) - Customer Concentration Risk - Sales Revenue, Net	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Daiichi Sankyo, Inc ("Daiichi")
Concentration Risk [Line Items]
Concentration risk percentage	41.00%	48.00%
Bayer Pharma, AG ('Bayer") and Janssen Pharmaceuticals, Inc. ("Janssen")
Concentration Risk [Line Items]
Concentration risk percentage	40.00%	34.00%
Bristol-Myers Squibb Company ("BMS") and Pfizer Inc. ("Pfizer")
Concentration Risk [Line Items]
Concentration risk percentage	15.00%	16.00%

Fair Value of Financial Assets,

Fair Value of Financial Assets, and Liabilities, Allocated into Level 1, Level 2, and Level 3 Measured on Recurring Basis (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Financial Assets:
Total financial assets	$ 375,452	$ 444,983
Fair Value, Inputs, Level 1
Financial Assets:
Total financial assets	29,876	22,074
Fair Value, Inputs, Level 2
Financial Assets:
Total financial assets	345,576	422,909
Money market funds
Financial Assets:
Total financial assets	29,876	22,074
Money market funds | Fair Value, Inputs, Level 1
Financial Assets:
Total financial assets	29,876	22,074
Corporate notes and commercial paper
Financial Assets:
Total financial assets	217,971	242,033
Corporate notes and commercial paper | Fair Value, Inputs, Level 2
Financial Assets:
Total financial assets	217,971	242,033
U.S. government agency securities
Financial Assets:
Total financial assets	127,605	180,876
U.S. government agency securities | Fair Value, Inputs, Level 2
Financial Assets:
Total financial assets	$ 127,605	$ 180,876

Fair Values Measurements - Addi

Fair Values Measurements - Additional Information (Detail) - USD ($)	Mar. 31, 2016	Dec. 31, 2015
Fair Value Disclosures [Abstract]
Fair value assets transfers from level 1 to level 2	$ 0	$ 0
Fair value assets transfers from level 2 to level 1	$ 0	$ 0

Cash Equivalents and Investment

Cash Equivalents and Investments Classified as Available-for-sale Securities (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Schedule Of Available For Sale Securities [Line Items]
Cost	$ 375,386	$ 445,133
Unrealized Gains	76	4
Unrealized (Losses)	(10)	(154)
Estimated Fair Value	375,452	444,983
Money market funds
Schedule Of Available For Sale Securities [Line Items]
Cost	29,876	22,074
Estimated Fair Value	29,876	22,074
Corporate notes and commercial paper
Schedule Of Available For Sale Securities [Line Items]
Cost	217,955	242,089
Unrealized Gains	19	3
Unrealized (Losses)	(3)	(59)
Estimated Fair Value	217,971	242,033
U.S. government agency securities
Schedule Of Available For Sale Securities [Line Items]
Cost	127,555	180,970
Unrealized Gains	57	1
Unrealized (Losses)	(7)	(95)
Estimated Fair Value	127,605	180,876
Cash equivalents
Schedule Of Available For Sale Securities [Line Items]
Estimated Fair Value	165,177	171,310
Short-term investments
Schedule Of Available For Sale Securities [Line Items]
Estimated Fair Value	$ 210,275	257,713
Long-term investments
Schedule Of Available For Sale Securities [Line Items]
Estimated Fair Value		$ 15,960

Financial Instruments - Additio

Financial Instruments - Additional Information (Detail) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Investments Debt And Equity Securities [Abstract]
Available For Sale Securities Contractual Maturity	1 year	2 years
Available-for-sale Securities, Gross Realized Gain (Loss)	$ 0	$ 0

Summary of Revenue from Collabo

Summary of Revenue from Collaboration and License Agreements (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaboration and license revenue	$ 8,258	$ 2,359
Daiichi Sankyo, Inc ("Daiichi")
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaboration and license revenue	3,385	1,128
Bayer Pharma, AG ('Bayer") and Janssen Pharmaceuticals, Inc. ("Janssen")
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaboration and license revenue	3,307	799
Bristol-Myers Squibb Company ("BMS") and Pfizer Inc. ("Pfizer")
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaboration and license revenue	1,254	380
Bayer Pharma AG
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaboration and license revenue	260
Lee’s Pharmaceutical (HK) Ltd (“Lee’s”)
Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]
Collaboration and license revenue	$ 52	$ 52

Collaboration and License Agr31

Collaboration and License Agreements - Additional Information (Detail) - USD ($)

1 Months Ended

3 Months Ended

6 Months Ended

24 Months Ended

Mar. 31, 2016

Feb. 29, 2016

Jul. 31, 2014

Apr. 30, 2014

Jan. 31, 2014

Feb. 28, 2013

Jan. 31, 2013

Nov. 30, 2012

Mar. 31, 2016

Sep. 30, 2015

Mar. 31, 2015

Sep. 30, 2014

Jun. 30, 2014

Jun. 30, 2013

Dec. 31, 2015

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaboration and license revenue

$ 8,258,000

$ 2,359,000

Research and development

58,813,000

39,858,000

Daiichi Sankyo, Inc ("Daiichi")

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaborative arrangement upfront payment to be received

$ 6,000,000

Upfront fee subject to refund

$ 3,000,000

Non-contingent consideration being recognized as revenue over estimated period of performance

$ 3,000,000

Contingent consideration to be recognized after resolution of contingency

$ 3,000,000

Contingent and non-contingent consideration to be recognized after resolution of contingency

258,000

Deferred revenue

$ 0

0

Upfront fee

$ 15,000,000

Contingent payment receivable upon achievement

5,000,000

Milestone Payments of Development and Regulatory Event

$ 20,000,000

Collaboration and license revenue

3,385,000

1,128,000

Daiichi Sankyo, Inc ("Daiichi") | March 2016 Agreement

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Deferred revenue

5,000,000

5,000,000

Collaboration and license revenue

5,000

Daiichi Sankyo, Inc ("Daiichi") | Future Contingent Payments | March 2016 Agreement

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaboration and license revenue

0

Daiichi Sankyo, Inc ("Daiichi") | Collaborative Agreement to Study Safety and Efficacy of Andexanet Alfa

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Deferred revenue

$ 8,800,000

8,800,000

Collaboration and license revenue

3,400,000

871,000

Daiichi Sankyo, Inc ("Daiichi") | Collaborative Agreement to Study Safety and Efficacy of Andexanet Alfa | Future Contingent Payments

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaboration and license revenue

2,500,000

0

Daiichi Sankyo, Inc ("Daiichi") | ESS-Study | March 2016 Agreement

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Reimbursement of costs and expenses percentage

33.00%

Daiichi Sankyo, Inc ("Daiichi") | Edoxaban | March 2016 Agreement | Minimum

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Reimbursement of costs and expenses percentage

33.00%

Daiichi Sankyo, Inc ("Daiichi") | Edoxaban | March 2016 Agreement | Maximum

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Reimbursement of costs and expenses percentage

100.00%

Bayer Pharma, AG ('Bayer") and Janssen Pharmaceuticals, Inc. ("Janssen")

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Upfront fee

$ 5,000,000

$ 10,000,000

$ 5,000,000

Contingent payment receivable upon achievement

10,000,000

7,000,000

Milestone Payments of Development and Regulatory Event

8,000,000

Collaboration and license revenue

3,307,000

799,000

Reduced contingent payment receivable upon achievement

7,000,000

Additional non-refundable fee

500,000

Bayer Pharma, AG ('Bayer") and Janssen Pharmaceuticals, Inc. ("Janssen") | February 2013 Agreement

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaborative Arrangement Payment Received

$ 500,000

Bayer Pharma, AG ('Bayer") and Janssen Pharmaceuticals, Inc. ("Janssen") | January 2014 Agreement

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Deferred revenue

6,500,000

6,500,000

Collaboration and license revenue

3,300,000

799,000

Contingent Payments Received

$ 3,000,000

Bayer Pharma, AG ('Bayer") and Janssen Pharmaceuticals, Inc. ("Janssen") | Future Contingent Payments | January 2014 Agreement

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaboration and license revenue

2,500,000

0

Bayer Pharma AG

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Upfront fee

$ 5,000,000

2,500,000

Contingent payment receivable upon achievement

10,000,000

Collaboration and license revenue

260,000

Reduced contingent payment receivable upon achievement

$ 7,000,000

Additional non-refundable fee

250,000

Bayer Pharma AG | February 2016 Agreement

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Deferred revenue

4,700,000

4,700,000

Collaboration and license revenue

260,000

Bayer Pharma AG | Future Contingent Payments | February 2016 Agreement

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Collaboration and license revenue

0

Bayer Pharma AG | ESS-Study | February 2016 Agreement

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Reimbursement of costs and expenses percentage

33.00%

Bayer Pharma AG | Rivaroxaban | February 2016 Agreement | Minimum

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Reimbursement of costs and expenses percentage

33.00%

Bayer Pharma AG | Rivaroxaban | February 2016 Agreement | Maximum

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Reimbursement of costs and expenses percentage

100.00%

Janssen Pharmaceuticals, Inc.

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Upfront fee

2,500,000

Additional non-refundable fee

$ 250,000

Bristol-Myers Squibb Company ("BMS") and Pfizer Inc. ("Pfizer")

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Non-contingent consideration being recognized as revenue over estimated period of performance

6,500,000

Contingent consideration to be recognized after resolution of contingency

6,500,000

Upfront fee

13,000,000

Contingent payment receivable upon achievement

4,000,000

Milestone Payments of Development and Regulatory Event

$ 12,000,000

Collaboration and license revenue

1,254,000

380,000

Percentage of consideration received under agreement

50.00%

Milestone payments of regulatory and clinical event

2,800,000

Milestone payments which remains payable

750,000

Bristol-Myers Squibb Company ("BMS") and Pfizer Inc. ("Pfizer") | January 2014 Agreement

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Deferred revenue

12,200,000

12,200,000

Collaboration and license revenue

475,000

380,000

Bristol-Myers Squibb Company ("BMS") and Pfizer Inc. ("Pfizer") | February 2016 Agreement

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Deferred revenue

14,200,000

14,200,000

Collaboration and license revenue

$ 779,000

Upfront fee

$ 15,000,000

Contingent payment receivable upon achievement of regulatory events

20,000,000

Contingent payment receivable upon achievement of annual net sales volumes

$ 70,000,000

Bristol-Myers Squibb Company ("BMS") and Pfizer Inc. ("Pfizer") | February 2016 Agreement | Minimum

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Percentage of royalties entitle to receive under agreement

5.00%

Bristol-Myers Squibb Company ("BMS") and Pfizer Inc. ("Pfizer") | February 2016 Agreement | Maximum

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Percentage of royalties entitle to receive under agreement

15.00%

Lee’s Pharmaceutical (HK) Ltd (“Lee’s”)

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Deferred revenue

$ 0

$ 0

200,000

Upfront fee

$ 700,000

Collaboration and license revenue

$ 52,000

52,000

Notice period for agreement termination

60 days

Ora, Inc. (“Ora”)

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Notice period for agreement termination

90 days

Development costs, percent

60.00%

Percentage of profits entitle to receive under agreement

50.00%

Rights to buy compound interests and licensed agreements

Each party may also buy out the rights and interests in the licensed compound by paying the greater of $6.0 million or two times the actual aggregate development cost incurred by both parties before or 90 days after an End of Phase 2 meeting with the FDA.

Research and development

$ 351,000

Ora, Inc. (“Ora”) | PORTOLA PHARMACEUTICALS INC

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

Development costs, percent

40.00%

Biogen Idec

Collaborative Arrangements And Noncollaborative Arrangement Transactions [Line Items]

License fee receivable upon occurrence of certain development and regulatory events

$ 370,000,000

Payments Upon the Completion of Certain Commercial Milestones

$ 15,000,000

Reduction in research and development expense

$ 0

$ 0

Commercial Supply Agreement - A

Commercial Supply Agreement - Additional Information (Detail) - USD ($)		1 Months Ended	3 Months Ended
		Jul. 31, 2014	Mar. 31, 2016	Dec. 31, 2015	Nov. 01, 2014
Long Term Purchase Commitment [Line Items]
Prepaid and other long-term assets	[1]		$ 11,177,000	$ 11,993,000
Prepaid research and development	[1]		10,854,000	16,976,000
Accrued research and development	[1]		17,574,000	$ 24,195,000
CMC ICOS Biologics Inc
Long Term Purchase Commitment [Line Items]
Commercial supply agreement upfront payment		$ 10,000,000
Commercial supply (manufacturing services) agreement reservation payment					$ 4,600,000
Commercial agreement fixed commitment amount		276,100,000
Payment made for purchases of batches related to commercial supply agreement since inception			$ 40,700,000
Term of commercial supply agreement			7 years
Purchases of batches recorded in prepaid research and development			$ 7,700,000
Accrued research and development			857,000
CMC ICOS Biologics Inc | Upfront and Reservation Payment
Long Term Purchase Commitment [Line Items]
Prepaid expenses and other assets			14,600,000
Prepaid and other long-term assets			10,600,000
Prepaid research and development			$ 2,800,000
CMC ICOS Biologics Inc | Minimum
Long Term Purchase Commitment [Line Items]
Termination fees payment under obligation		5,000,000
CMC ICOS Biologics Inc | Maximum
Long Term Purchase Commitment [Line Items]
Termination fees payment under obligation		$ 30,000,000
[1]	Amounts include the assets and liabilities of our Development Partner a consolidated variable interest entity (“VIE”). Portola's interests and obligations with respect to the VIE's assets and liabilities are limited to those accorded to Portola in its agreement with the VIE. See Note 7, “Asset Acquisition and License Agreements,” to these condensed consolidated financial statements.

Asset Acquisition and License33

Asset Acquisition and License Agreements - Additional Information (Detail) - USD ($)		1 Months Ended	3 Months Ended
		Dec. 31, 2015	Mar. 31, 2016	Dec. 01, 2015
Asset Acquisition [Line Items]
Restricted cash (Development Partner)	[1]	$ 341,000	$ 262,000
Development Partner
Asset Acquisition [Line Items]
Variable interest entity, Terms of arrangements			Accordingly, the Development Partner is subject to consolidation and we have consolidated the financial statements of the Development Partner since inception of the agreement on December 1, 2015 by (a) eliminating all intercompany balances and transactions; (b) allocating loss attributable to the noncontrolling interest in the Development Partner to net loss attributable to noncontrolling interest in our consolidated statement of operations and reflecting noncontrolling interest on our consolidated balance sheet.
Variable interest entity, Upfront payment		$ 500,000
Fair value of indefinite lived intangible assets				$ 3,200,000
Noncontrolling interest in variable Interest entity				$ 2,900,000
Restricted cash (Development Partner)			$ 262,000
Net loss attributable to noncontrolling interest (Development Partner)			$ 0
[1]	Amounts include the assets and liabilities of our Development Partner a consolidated variable interest entity (“VIE”). Portola's interests and obligations with respect to the VIE's assets and liabilities are limited to those accorded to Portola in its agreement with the VIE. See Note 7, “Asset Acquisition and License Agreements,” to these condensed consolidated financial statements.

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015	Jan. 31, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage increase in number of common stock outstanding			5.00%
Shares reserved for future issuance	12,205,425
Stock-based compensation expense	$ 7,069,000	$ 5,172,000
Performance Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense	$ 0
Performance Shares | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Performance-based RSUs awarded based on achievement of development goals, available for grant				102,906

Summary of Stock Option Activit

Summary of Stock Option Activity (Detail)	3 Months Ended
	Mar. 31, 2016$ / sharesshares
Shares Subject to Outstanding Stock Options
Beginning balance | shares	4,731,483
Options granted | shares	980,215
Options exercised | shares	(10,984)
Options canceled | shares	(85,230)
Ending balance | shares	5,615,484
Weighted-Average Exercise Price Per Share
Beginning balance | $ / shares	$ 24.19
Options granted | $ / shares	32.51
Options exercised | $ / shares	15.52
Options canceled | $ / shares	28.85
Ending balance | $ / shares	$ 25.59

Estimated Grant Date Fair Value

Estimated Grant Date Fair Values of Employee Stock Options (Detail) - Employee Stock Option	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate	1.61%	1.54%
Expected life	6 years	6 years
Expected volatility	64.00%	66.00%
Dividend yield	0.00%	0.00%

Summary of RSU Activity (Detail

Summary of RSU Activity (Detail) - Restricted Stock Units (RSUs)	3 Months Ended
	Mar. 31, 2016$ / sharesshares
Shares Subject to Outstanding Options
Beginning balance | shares	167,750
RSUs granted | shares	215,655
RSUs released | shares	(55,195)
RSUs canceled | shares	(9,982)
Ending balance | shares	318,228
Weighted-Average Exercise Price Per Share
Beginning balance | $ / shares	$ 30.86
RSUs granted | $ / shares	33.49
RSUs released | $ / shares	30.88
RSUs canceled | $ / shares	31.67
Ending balance | $ / shares	$ 32.62

Summary of PSU Activity (Detail

Summary of PSU Activity (Detail) - 2013 Equity Incentive Plan - Performance Shares	3 Months Ended
	Mar. 31, 2016$ / sharesshares
Shares Subject to Outstanding Options
Beginning balance | shares	205,261
RSUs granted | shares	102,906
RSUs released | shares	(13,170)
RSUs canceled | shares	(1,303)
Ending balance | shares	293,694
Weighted-Average Exercise Price Per Share
Beginning balance | $ / shares	$ 29.33
RSUs granted | $ / shares	33.49
RSUs released | $ / shares	50
RSUs canceled | $ / shares	49.44
Ending balance | $ / shares	$ 29.77

Classification of Stock-Based C

Classification of Stock-Based Compensation Expense (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation	$ 7,069	$ 5,172
Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation	3,030	2,209
Selling, General and Administrative Expenses
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation	$ 4,039	$ 2,963

Common Stock Equivalent Shares

Common Stock Equivalent Shares Excluded from Computation of Diluted Net Loss per Share (Detail) - shares	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Stock options to purchase common stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Common stock equivalents excluded from computation of diluted net loss per share	5,615,484	4,787,869
Common stock warrants
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Common stock equivalents excluded from computation of diluted net loss per share	1,500	1,500
Restricted Stock Units (RSUs)
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Common stock equivalents excluded from computation of diluted net loss per share	318,228	171,787
Performance Shares
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Common stock equivalents excluded from computation of diluted net loss per share	293,694	140,000

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - USD ($)	1 Months Ended		3 Months Ended
	May. 31, 2016	Apr. 30, 2016	Mar. 31, 2016
Subsequent Event [Line Items]
Options granted			980,215
Restricted Stock Units (RSUs)
Subsequent Event [Line Items]
RSUs granted			215,655
Subsequent Event
Subsequent Event [Line Items]
Non-cancellable purchase commitments		$ 6,000,000
Subsequent Event | Management Team
Subsequent Event [Line Items]
Options granted	271,122
Subsequent Event | Employee Stock Option
Subsequent Event [Line Items]
Options granted	510,593
Subsequent Event | Restricted Stock Units (RSUs)
Subsequent Event [Line Items]
RSUs granted	255,301
Maximum | Subsequent Event
Subsequent Event [Line Items]
Termination fees payment under obligation		$ 34,000,000