Document and Entity Information - shares	3 Months Ended
Document and Entity Information - shares	Mar. 31, 2017	May 04, 2017
Document and Entity Information
Entity Registrant Name	Corvus Pharmaceuticals, Inc.
Entity Central Index Key	0001626971
Document Type	10-Q
Document Period End Date	Mar. 31, 2017
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		20,934,514
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	Q1

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 10,487	$ 5,050
Marketable securities	111,577	129,846
Prepaid and other current assets	1,051	1,137
Total current assets	123,115	136,033
Property and equipment, net	3,117	3,248
Other assets	869	869
Total assets	127,101	140,150
Current liabilities:
Accounts payable	2,421	1,900
Accrued and other liabilities	5,158	4,044
Total current liabilities	7,579	5,944
Other liabilities	1,297	1,405
Total liabilities	8,876	7,349
Commitments and contingencies (Note 11)
Stockholders' equity:
Preferred stock: $0.0001 par value; 10,000,000 shares authorized at March 31, 2017 and December 31, 2016; 0 shares issued and outstanding at March 31, 2017 and December 31, 2016
Common stock: $0.0001 par value; 290,000,000 shares authorized at March 31, 2017 and December 31, 2016; 20,934,514 and 20,922,428 shares issued and outstanding at March 31, 2017 and December 31, 2016 respectively	2	2
Additional paid-in capital	202,192	200,709
Accumulated other comprehensive loss	(62)	(39)
Accumulated deficit	(83,907)	(67,871)
Total stockholders' equity	118,225	132,801
Total liabilities and stockholders' equity	$ 127,101	$ 140,150

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Mar. 31, 2017	Dec. 31, 2016
CONDENSED CONSOLIDATED BALANCE SHEETS
Preferred stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized	290,000,000	290,000,000
Common stock, shares issued	20,934,514	20,922,428
Common stock, shares outstanding	20,934,514	20,922,428

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Operating expenses:
Research and development	$ 13,497	$ 5,397
General and administrative	2,720	1,029
Total operating expenses	16,217	6,426
Loss from operations	(16,217)	(6,426)
Interest income	181	79
Net loss	$ (16,036)	$ (6,347)
Net loss per share, basic and diluted (in dollars per share)	$ (0.79)	$ (5.39)
Shares used to compute net loss per share, basic and diluted (in shares)	20,349,391	1,176,546
Other comprehensive income (loss):
Unrealized (loss) gain on marketable securities	$ (23)	$ 74
Comprehensive loss	$ (16,059)	$ (6,273)

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Cash flows from operating activities
Net loss	$ (16,036)	$ (6,347)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	204	106
Amortization/accretion related to marketable securities	(19)	105
Stock-based compensation	1,468	441
Changes in operating assets and liabilities:
Prepaid and other current assets	63	(347)
Other assets		(600)
Accounts payable	559	(193)
Accrued and other liabilities	1,121	618
Other long-term liabilities	(108)	581
Net cash used in operating activities	(12,748)	(5,636)
Cash flows from investing activities
Purchases of marketable securities	(18,012)	(91,133)
Maturities of marketable securities	36,300	33,000
Purchase of property and equipment	(111)	(614)
Net cash provided by (used in) investing activities	18,177	(58,747)
Cash flows from financing activities
Proceeds from issuance of common stock, net of issuance costs		64,343
Proceeds from exercise of common stock options	8
Net cash provided by financing activities	8	64,343
Net increase (decrease) in cash and cash equivalents	5,437	(40)
Cash and cash equivalents at beginning of the period	5,050	4,105
Cash and cash equivalents at end of the period	10,487	4,065
Supplemental disclosures of cash flow information
Purchases of property and equipment incurred but not paid	$ 46	199
IPO costs incurred but not paid		$ 301

Organization	3 Months Ended
Organization	Mar. 31, 2017
Organization
Organization	1. Organization Corvus Pharmaceuticals, Inc. (“Corvus” or the “Company”) was incorporated in Delaware on January 27, 2014 and commenced operations in November 2014. Corvus is a clinical-stage biopharmaceutical company focused on the development and commercialization of novel immuno-oncology therapies that are designed to harness the immune system to attack cancer cells. The Company’s primary activities have been establishing its facilities, recruiting personnel, conducting research and development of its product candidates, including conducting a clinical trial, and raising capital. The Company’s operations are located in Burlingame, California. The Company has four insignificant subsidiaries. Initial Public Offering On March 22, 2016, the Company’s registration statement on Form S-1 (File No. 333-208850) relating to its initial public offering (“IPO”) of its common stock was declared effective by the Securities and Exchange Commission (“SEC”) and the shares of its common stock began trading on the NASDAQ Global Market on March 23, 2016. The public offering price of the shares sold in the IPO was $15.00 per share. The IPO closed on March 29, 2016, pursuant to which the Company sold 4,700,000 shares of its common stock. On April 26, 2016, the Company sold an additional 502,618 shares of its common stock to the underwriters upon partial exercise of their over-allotment option, at the initial offering price of $15.00 per share. The Company received aggregate net proceeds of approximately $70.6 million, after underwriting discounts, commissions and offering expenses. Immediately prior to the consummation of the IPO, all outstanding shares of convertible preferred stock were converted into common stock.

Summary of Significant Accounting Policies	3 Months Ended
Summary of Significant Accounting Policies	Mar. 31, 2017
Summary of Significant Accounting Policies
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation The accompanying condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”). The Company’s functional and reporting currency is the U.S. dollar. The accompanying condensed consolidated financial statements have been prepared on a going concern basis, which contemplates the realization of assets and discharge of liabilities in the normal course of business. Since its inception, the Company has incurred significant losses and negative cash flows from operations. During the three months ended March 31, 2017, the Company incurred a net loss of $16.0 million and used $12.7 million of cash in operations. As of March 31, 2017, the Company had an accumulated deficit of $83.9 million and cash, cash equivalents and marketable securities of $122.1 million. The Company has financed its operations primarily with the proceeds from the sale of stock. The Company will need to raise additional capital to meet its business objectives. The Company believes that its current cash, cash equivalents and marketable securities will be sufficient to fund its planned expenditures and meet its obligations through at least the next twelve months. Unaudited Interim Financial Information The accompanying interim condensed consolidated financial statements and related disclosures are unaudited, have been prepared on the same basis as the annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for a fair statement of the results of operations for the periods presented. The year-end condensed consolidated balance sheet data was derived from audited financial statements, but does not include all disclosures required by GAAP. The condensed consolidated results of operations for the three months ended March 31, 2017 are not necessarily indicative of the results to be expected for the full year or for any other future year or interim period. The accompanying condensed consolidated financial statements should be read in conjunction with the audited financial statements and the related notes for the year ended December 31, 2016 included in the Company’s Annual Report on Form 10-K filed with the SEC on March 10, 2017. Use of Estimates The preparation of the Company’s condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the condensed consolidated financial statements and accompanying notes. Actual results could differ from such estimates. Concentrations of Credit Risk and Other Risks and Uncertainties Substantially all of the Company’s cash and cash equivalents are deposited in accounts with two financial institutions that management believes are of high credit quality. Such deposits may, at times, exceed federally insured limits. The Company maintains its cash with an accredited financial institution and accordingly, such funds are subject to minimal credit risk. The Company’s marketable securities are direct obligations of the United States government. The Company has not experienced any losses on its deposits of cash, cash equivalents or marketable securities. The Company is subject to a number of risks similar to other early stage biopharmaceutical companies, including, but not limited to, the need to obtain adequate additional funding, possible failure of preclinical testing or clinical trials, its reliance on third parties to conduct its clinical trials, the need to obtain marketing approval for its product candidates, competitors developing new technological innovations, the need to successfully commercialize and gain market acceptance of the Company’s product candidates, its right to develop and commercialize its product candidates pursuant to the terms and conditions of the licenses granted to the Company, and protection of proprietary technology. If the Company does not successfully commercialize or partner any of its product candidates, it will be unable to generate product revenue or achieve profitability. Segments Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker in making decisions regarding resource allocation and assessing performance. The Company views its operations and manages its business in one operating segment, that of the development of and commercialization of novel immuno-oncology therapies that are designed to harness the immune system to attack cancer cells. Critical Accounting Policies The Company’s critical accounting policies are described in Note 2 to our consolidated financial statements for the year ended December 31, 2016, included in our Annual Report on Form 10-K. There have been no material changes to the Company’s critical accounting policies during the three months ended March 31, 2017. Recent Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2014-09, Revenue from Contracts with Customers, which required an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. ASU No. 2014-09 will replace most existing revenue recognition guidance in U.S. GAAP when it becomes effective. The new standard is effective January 1, 2018 for public companies. Early application is permitted as of January 1, 2017. The standard permits the use of either the retrospective or cumulative effect transition method. In March 2016, the FASB issued ASU No. 2016-08, Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations (Reporting Revenue Gross versus Net), which clarifies the implementation guidance on principal versus agent considerations in ASU No. 2014-09. In April 2016, the FASB issued ASU No. 2016-10, Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing, which clarifies certain aspects of identifying performance obligations and licensing implementation guidance. In May 2016, the FASB issued ASU No. 2016-12, Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients, which relates to disclosures of remaining performance obligations, as well as other amendments to guidance on collectability, non-cash consideration and the presentation of sales and other similar taxes collected from customers. These standards have the same effective date and transition date of January 1, 2018. The Company does not believe adopting this guidance will have a material impact on its consolidated financial statements as the Company is not yet generating revenues. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) that replaces existing lease guidance. The new standard requires lessees to record right of use assets and corresponding lease liabilities on the balance sheet. The new guidance will continue to classify leases as either finance or operating, with classification affecting the pattern of expense recognition in the statement of income. The standard is effective for the Company beginning January 1, 2019, with early application permitted. The new standard is required to be applied with a modified retrospective approach to each prior reporting period presented with various optional practical expedients. The Company is currently assessing the impact of this guidance on its consolidated financial statements.

Net Loss per Share

3 Months Ended

Mar. 31, 2017

Net Loss per Share

Net Loss per Share

3. Net Loss per Share

The following table shows the calculation of net loss per share (in thousands, except share and per share data):

	Three Months Ended
	March 31,
	2017			2016
Numerator:
Net loss - basic and diluted	$	(16,036	)	$	(6,347	)

Denominator:
Weighted average common shares outstanding	20,929,110			2,057,200
Less: weighted average common shares subject to repurchase	(579,719		)	(880,654		)

Weighted average common shares outstanding used to compute basic and diluted net loss per share	20,349,391			1,176,546

Net loss per share, basic and diluted	$	(0.79	)	$	(5.39	)

The amounts in the table below were excluded from the calculation of diluted net loss per share, due to their anti-dilutive effect:

	March 31,
	2017	2016
Common stock subject to repurchase	538,575	840,235
Outstanding options	2,358,272	1,787,386

Total shares of common stock equivalents	2,896,847	2,627,621

Fair Value Measurements

3 Months Ended

Mar. 31, 2017

Fair Value Measurements

Fair Value Measurements

4. Fair Value Measurements

Financial assets and liabilities are measured and recorded at fair value. The Company is required to disclose information on all assets and liabilities reported at fair value that enables an assessment of the inputs used in determining the reported fair values. The fair value hierarchy prioritizes valuation inputs based on the observable nature of those inputs. The fair value hierarchy applies only to the valuation inputs used in determining the reported fair value of the investments and is not a measure of the investment credit quality. The hierarchy defines three levels of valuation inputs:

Level 1—Quoted prices in active markets for identical assets or liabilities

Level 2—Inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly

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

There have been no transfers of assets and liabilities between levels of hierarchy.

The following tables present information as of March 31, 2017 and December 31, 2016 about the Company’s assets that are measured at fair value on a recurring basis and indicate the level of the fair value hierarchy the Company utilized to determine such fair values (in thousands):

	March 31, 2017
	Fair Value Measured Using						Total
	(Level 1)		(Level 2)		(Level 3)		Balance
Assets
Cash equivalents	$	8,436	$	—	$	—	$	8,436
Marketable securities	111,577		—		—		111,577

	$	120,013	$	—	$	—	$	120,013

	December 31, 2016
	Fair Value Measured Using						Total
	(Level 1)		(Level 2)		(Level 3)		Balance
Assets
Cash equivalents	$	2,999	$	—	$	—	$	2,999
Marketable securities	129,846		—		—		129,846

	$	132,845	$	—	$	—	$	132,845

The Company’s marketable securities are invested in direct obligations of the United States government for all periods.

As of March 31, 2017, marketable securities had a maximum remaining maturity of eight months and consisted of U.S. Treasury securities.

As of March 31, 2017 and December 31, 2016, the fair value of available for sale marketable securities by type of security were as follows (in thousands):

	March 31, 2017
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
U.S. Treasury securities	$	111,639	$	—	$	(62	)	$	111,577

	December 31, 2016
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
U.S. Treasury securities	$	129,885	$	—	$	(39	)	$	129,846

- Definition

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

+ References + Details

License and Collaboration Agreements	3 Months Ended
License and Collaboration Agreements	Mar. 31, 2017
License and Collaboration Agreements
License and Collaboration Agreements	5. License and Collaboration Agreements Scripps Licensing Agreement In December 2014, the Company entered into a license agreement with The Scripps Research Institute (“Scripps”), pursuant to which it was granted a non-exclusive, world-wide license for all fields of use under Scripps’ rights in certain know-how and technology related to a mouse hybridoma clone expressing an anti-human CD73 antibody, and to progeny, mutants or unmodified derivatives of such hybridoma and any antibodies expressed by such hybridoma. Scripps also granted the Company the right to grant sublicenses in conjunction with other proprietary rights the Company holds, or to others collaborating with or performing services for the Company. Under this license agreement, Scripps has agreed not to grant any additional commercial licenses with respect to such materials, other than march-in rights granted to the U.S. government. Upon execution of the agreement, the Company made a one-time cash payment to Scripps of $10,000 in 2015 and is also obligated to pay a minimum annual fee to Scripps of $25,000. The one-time cash payment was recorded as research and development expense as technological feasibility of the asset had not been established and there was no alternative future use. The first minimum annual fee payment is due on the first anniversary of effective date of the agreement and will be due on each subsequent anniversary of the effective date for the term of the agreement. The Company is also required to make performance-based cash payments upon successful completion of clinical and sales milestones. The aggregate potential milestone payments are $2.6 million. The Company is also required to pay royalties on net sales of licensed products sold by it, its affiliates and its sublicensees at a rate in the low-single digits. In addition, should the Company sublicense the rights licensed under the agreement, it has agreed to pay a percentage of sublicense revenue received at specified rates that start at double digit percentages and decrease to single digit percentages based on the elapsed time from the effective date of the agreement and the time of entry into such sublicense. To date, no milestone payments have been made. The Company’s license agreement with Scripps will terminate upon expiration of its obligation to pay royalties to Scripps under the license agreement. The Company’s license agreement with Scripps is terminable by the consent of the parties, at will by the Company upon providing 90 days written notice to Scripps, or by Scripps for certain material breaches, or if the Company undergoes a bankruptcy event. In addition, Scripps may terminate the license on a product-by-product basis, or the entire agreement, if the Company fails to meet specified diligence obligations related to the development and commercialization of licensed products. Scripps may also terminate the agreement after the third anniversary of the effective date of the agreement if it reasonably believes, based on reports the Company provides to Scripps, that the Company has not used commercially reasonable efforts as required under the agreement, subject to a specified notice and cure period. Vernalis Licensing Agreement In February 2015, the Company entered into a license agreement with Vernalis (R&D) Limited (“Vernalis”), which was subsequently amended as of November 5, 2015, and, pursuant to which the Company was granted an exclusive, worldwide license under certain patent rights and know-how, including a limited right to grant sublicenses, for all fields of use to develop, manufacture and commercialize products containing certain adenosine receptor antagonists, including CPI-444. Pursuant to this agreement, the Company made a one-time cash payment to Vernalis in the amount of $1.0 million, which was recorded as research and development expense as technological feasibility of the asset had not been established and there was no alternative future use. The Company is also required to make cash milestone payments to Vernalis upon the successful completion of clinical and regulatory milestones for licensed products depending on the indications for which such licensed products are developed and upon achievement of certain sales milestones. In February 2017, the Company made a milestone payment of $3.0 million to Vernalis following the expansion of a cohort of patients with renal cell cancer treated with single agent CPI-444 in the Company’s Phase 1/1b clinical trial. The aggregate potential milestone payments exceed $200 million for all indications. The Company has also agreed to pay Vernalis tiered incremental royalties based on the annual net sales of licensed products containing CPI-444 on a product-by-product and country-by-country basis, subject to certain offsets and reductions. The tiered royalty rates for products containing CPI-444 range from the mid-single digits up to the low-double digits on a country-by-country net sales basis. The royalties on other licensed products that do not include CPI-444 also increase with the amount of net sales on a product-by-product and country-by-country basis and range from the low-single digits up to the mid-single digits on a country-by-country net sales basis. The Company is also obligated to pay to Vernalis certain sales milestones as indicated above when worldwide net sales reach specified levels over an agreed upon time period. The agreement will expire on a product-by-product and country-by-country basis upon the expiration of the Company’s payment obligations to Vernalis in respect of a particular product and country. Both parties have the right to terminate the agreement for an uncured material breach by the other party. The Company may also terminate the agreement at its convenience by providing 90 days written notice, provided that the Company has not received notice of its own default under the agreement at the time the Company exercises such termination right. Vernalis may also terminate the agreement if the Company challenges a licensed patent or undergoes a bankruptcy event. Genentech Collaboration Agreement In October 2015, the Company entered into a clinical trial collaboration agreement with Genentech to evaluate the safety, tolerability and preliminary efficacy of CPI-444 combined with Genentech’s investigational cancer immunotherapy, Tecentriq (atezolizumab), a fully humanized monoclonal antibody targeting protein programmed cell death ligand 1(“PD-L1”), in a variety of solid tumors in a Phase 1/1b clinical trial. Pursuant to this agreement, the Company will be responsible for the conduct and cost of the relevant studies, under the supervision of a joint development committee made up of representatives of the Company and representatives of Genentech. Genentech will supply Tecentriq. As part of the agreement, the Company granted Genentech certain rights of first negotiation to participate in future clinical trials that the Company may conduct evaluating the administration of CPI-444 in combination with an anti-PD-1 or anti-PD-L1 antibody. If the Company and Genentech do not reach agreement on the terms of any such participation by Genentech within a specified time period, the Company retains the right to collaborate with third parties in such activities. The Company also granted Genentech certain rights of first negotiation should it decide to license development and commercialization rights to CPI-444. Should the Company and Genentech not reach agreement on the terms of such a license within a specified time period, it retains the right to enter into a license with another third party. The Company and Genentech each have the right to terminate the agreement for material breach by the other party. In addition, the agreement may be terminated by either party due to safety considerations, if directed by a regulatory authority or if development of CPI-444 or Tecentriq is discontinued. Further, the agreement will expire after a set period of time following the provision by the Company of the final clinical study report to Genentech.

Balance Sheet Components

3 Months Ended

Mar. 31, 2017

Balance Sheet Components

Balance Sheet Components

6. Balance Sheet Components (in thousands):

	March 31,			December 31,
	2017			2016
Prepaid and Other Current Assets
Interest receivable	$	53		$	365
Prepaid research and development manufacturing expenses	170			—
Other	828			772

	$	1,051		$	1,137

Property and Equipment, net
Laboratory equipment	$	1,933		$	1,868
Computer equipment and purchased software	66			58
Leasehold improvements	2,051			2,051

	4,050			3,977
Less: accumulated depreciation and amortization	(933		)	(729		)

	$	3,117		$	3,248

Accrued and Other Liabilities
Accrued clinical trial related	$	2,126		$	1,617
Accrued manufacturing expense	1,416			955
Personnel related	660			526
Deferred rent	386			378
Accrued legal and accounting	309			255
Other accrued expenses	261			313

	$	5,158		$	4,044

Other Liabilities
Deferred rent	$	1,269		$	1,370
Shares subject to vesting	28			35

	$	1,297		$	1,405

Common Stock

3 Months Ended

Mar. 31, 2017

Common Stock

Common Stock

7. Common Stock

As of March 31, 2017, the amended and restated certificate of incorporation authorizes the Company to issue 290 million shares of common stock and 10 million shares of preferred stock.

Each share of common stock is entitled to one vote. Common stockholders are entitled to dividends if and when declared by the board of directors. As of March 31, 2017, no dividends on common stock had been declared.

The Company has reserved shares of common stock, for issuance as follows:

	March 31,	December 31,
	2017	2016
Shares available for future option grants	3,285,824	2,475,600
Outstanding options	2,358,272	2,350,582
Unvested restricted common stock (founders and early exercise of stock options)	538,575	611,698
Shares reserved for employee stock purchase plan	400,000	200,000

Total	6,582,671	5,637,880

- Definition

The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
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-Section 50
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-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21506-112644

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
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-Section S99
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-Name Accounting Standards Codification
-Topic 505
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-Paragraph 1
-Subparagraph (SX 210.3-04)
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Reference 12: http://www.xbrl.org/2003/role/presentationRef
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Reference 13: http://www.xbrl.org/2003/role/presentationRef
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Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Preferred Stock
-URI http://asc.fasb.org/extlink&oid=6521494

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-Publisher FASB
-Name Accounting Standards Codification
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-Publisher FASB
-Name Accounting Standards Codification
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+ Details

Stock Option Plans

3 Months Ended

Mar. 31, 2017

Stock Option Plans

Stock Option Plans

8. Stock Option Plans

In February 2014, the Company adopted the 2014 Equity Incentive Plan (the “2014 Plan”), which was subsequently amended in November 2014, July 2015 and September 2015, under which it granted incentive stock options (“ISOs”) or non-qualified stock options (“NSOs”). Terms of stock agreements, including vesting requirements, are determined by the board of directors or a committee authorized by the board of directors, subject to the provisions of the 2014 Plan. In general, awards granted by the Company vest over four years and have a maximum exercise term of 10 years. The 2014 Plan provides that grants must be at an exercise price of 100% of fair market value of the Company’s common stock as determined by the board of directors on the date of the grant.

In connection with the consummation of the IPO in March 2016, the 2016 Equity Incentive Award Plan (the “2016 Plan”), became effective. Under the 2016 Plan, incentive stock options, non-statutory stock options, stock purchase rights and other stock-based awards may be granted. Terms of stock agreements, including vesting requirements, are determined by the board of directors or a committee authorized by the board of directors, subject to the provisions of the 2016 Plan. In general, awards granted by the Company vest over four years and have a maximum exercise term of 10 years. The 2016 Plan provides that grants must be at an exercise price of 100% of fair market value of the Company’s common stock as determined by the board of directors on the date of the grant. In conjunction with adopting the 2016 Plan, the 2014 Plan was terminated and no further awards will be granted under the 2014 Plan. Options outstanding under the 2014 Plan as of the effective date of the 2016 Plan that are forfeited or lapse unexercised may be re-issued under the 2016 Plan, up to a maximum of 1,136,229 shares.

Activity under the Company’s stock option plans is set forth below:

			Options Outstanding
					Weighted-
	Shares				Average
	Available		Number		Exercise
	for Grant		of Options		Price
Balance at December 31, 2016	2,475,600		2,350,582		$	11.88
Additional shares authorized	830,000		—		—
Options granted	(58,000	)	58,000		15.29
Options exercised	—		(12,086	)	0.64
Options forfeited	38,224		(38,224	)	9.56

Balance at March 31, 2017	3,285,824		2,358,272		$	12.06

Stock-Based Compensation

3 Months Ended

Mar. 31, 2017

Stock-Based Compensation

Stock-Based Compensation

9. Stock-Based Compensation

The Company’s results of operations include expenses relating to employee and non-employee stock-based awards as follows (in thousands):

	Three Months Ended
	March 31,
	2017		2016
Research and development	$	623	$	301
General and administrative	845		140

Total	$	1,468	$	441

- Definition

The entire disclosure for compensation-related costs for equity-based compensation, which may include disclosure of policies, compensation plan details, allocation of equity compensation, incentive distributions, equity-based arrangements to obtain goods and services, deferred compensation arrangements, employee stock ownership plan details and employee stock purchase plan details.

+ References + Details

Income Taxes	3 Months Ended
Income Taxes	Mar. 31, 2017
Income Taxes
Income Taxes	10. Income Taxes The Company did not record a provision or benefit for income taxes during the three months ended March 31, 2017 or 2016. The Company continues to maintain a full valuation allowance against its net deferred tax assets.

Commitments and Contingencies

3 Months Ended

Mar. 31, 2017

Commitments and Contingencies

Commitments and Contingencies

11. Commitments and Contingencies

Facility Lease

In January 2015, the Company signed an initial operating lease, effective February 1, 2015 for 8,138 square feet of office and laboratory space with a one-year term. Between January 2015 and August 2016, the Company entered into a series of lease amendments to increase the amount of leased space to 28,633 square feet and extend the expiration of the lease to February 2021. The lease agreement includes an annual rent escalation clause and a right to extend the term at the then current market rate for three years. Under the lease and subsequent amendments, the landlord provided approximately $1.9 million in free rent and lease incentives. The Company records rent expense on a straight-line basis over the effective term of the lease, including any free rent periods and incentives. The lease requires the Company to pay additional amounts for operating and maintenance expenses. Rent expense related to the facilities lease for the three months ended March 31, 2017 and 2016 was approximately $184,000 and $129,000, respectively. As of March 31, 2017, future minimum lease payments under the facility lease were as follows (in thousands):

Year Ended December 31:
2017 *	$	836
2018	1,143
2019	1,177
2020	1,211
2021	101

Total	$	4,468

*Remainder of the year

In August 2015 the Company entered into an agreement for a line of credit of $0.1 million for the purpose of issuing its landlord a letter of credit of $0.1 million as a security deposit under its facility lease. The Company pledged money market funds and marketable securities as collateral for the line of credit. Pursuant to the Company’s license agreements with each of Vernalis and Scripps, it has obligations to make future milestone and royalty payments to these parties, respectively. However, because these amounts are contingent and not fixed or determinable, they have not been included on the Company’s balance sheet.

Indemnifications

In the ordinary course of business, the Company enters into agreements that may include indemnification provisions. Pursuant to such agreements, the Company may indemnify, hold harmless and defend an indemnified party for losses suffered or incurred by the indemnified party. Some of the provisions will limit losses to those arising from third-party actions. In some cases, the indemnification will continue after the termination of the agreement. The maximum potential amount of future payments the Company could be required to make under these provisions is not determinable. The Company has never incurred material costs to defend lawsuits or settle claims related to these indemnification provisions. The Company has also entered into indemnification agreements with its directors and officers that may require the Company to indemnify its directors and officers against liabilities that may arise by reason of their status or service as directors or officers to the fullest extent permitted by Delaware corporate law. There have been no claims to date and the Company has a directors and officers insurance policy that may enable it to recover a portion of any amounts paid for future claims.

Legal Proceedings

The Company is not a party to any material legal proceedings.

Subsequent Event	3 Months Ended
Subsequent Event	Mar. 31, 2017
Subsequent Event
Subsequent Event	12. Subsequent Event On May 1, 2017, Corvus signed a new collaboration agreement with Genentech, a member of the Roche Group. Under the new agreement, CPI-444 administered in combination with Tecentriq (atezolizumab) will be evaluated in a Phase 1b/2 randomized, controlled clinical study as second-line therapy in patients with non-small cell lung cancer (NSCLC) who are resistant/refractory to prior therapy with an anti PD(L)-1 antibody. It is anticipated that the study will enroll up to 65 patients in the treatment arm. Genentech will manage study operations for the Phase 1b/2 trial, which is expected to begin enrolling patients in the second half of 2017. Corvus retains global development and commercialization rights to CPI-444.

Summary of Significant Accounting Policies (Policies)	3 Months Ended
Summary of Significant Accounting Policies (Policies)	Mar. 31, 2017
Summary of Significant Accounting Policies
Basis of Presentation	Basis of Presentation The accompanying condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (“U.S. GAAP”). The Company’s functional and reporting currency is the U.S. dollar. The accompanying condensed consolidated financial statements have been prepared on a going concern basis, which contemplates the realization of assets and discharge of liabilities in the normal course of business. Since its inception, the Company has incurred significant losses and negative cash flows from operations. During the three months ended March 31, 2017, the Company incurred a net loss of $16.0 million and used $12.7 million of cash in operations. As of March 31, 2017, the Company had an accumulated deficit of $83.9 million and cash, cash equivalents and marketable securities of $122.1 million. The Company has financed its operations primarily with the proceeds from the sale of stock. The Company will need to raise additional capital to meet its business objectives. The Company believes that its current cash, cash equivalents and marketable securities will be sufficient to fund its planned expenditures and meet its obligations through at least the next twelve months.
Unaudited Interim Financial Information	Unaudited Interim Financial Information The accompanying interim condensed consolidated financial statements and related disclosures are unaudited, have been prepared on the same basis as the annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for a fair statement of the results of operations for the periods presented. The year-end condensed consolidated balance sheet data was derived from audited financial statements, but does not include all disclosures required by GAAP. The condensed consolidated results of operations for the three months ended March 31, 2017 are not necessarily indicative of the results to be expected for the full year or for any other future year or interim period. The accompanying condensed consolidated financial statements should be read in conjunction with the audited financial statements and the related notes for the year ended December 31, 2016 included in the Company’s Annual Report on Form 10-K filed with the SEC on March 10, 2017.
Use of Estimates	Use of Estimates The preparation of the Company’s condensed consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the condensed consolidated financial statements and accompanying notes. Actual results could differ from such estimates.
Concentrations of Credit Risk and Other Risks and Uncertainties	Concentrations of Credit Risk and Other Risks and Uncertainties Substantially all of the Company’s cash and cash equivalents are deposited in accounts with two financial institutions that management believes are of high credit quality. Such deposits may, at times, exceed federally insured limits. The Company maintains its cash with an accredited financial institution and accordingly, such funds are subject to minimal credit risk. The Company’s marketable securities are direct obligations of the United States government. The Company has not experienced any losses on its deposits of cash, cash equivalents or marketable securities. The Company is subject to a number of risks similar to other early stage biopharmaceutical companies, including, but not limited to, the need to obtain adequate additional funding, possible failure of preclinical testing or clinical trials, its reliance on third parties to conduct its clinical trials, the need to obtain marketing approval for its product candidates, competitors developing new technological innovations, the need to successfully commercialize and gain market acceptance of the Company’s product candidates, its right to develop and commercialize its product candidates pursuant to the terms and conditions of the licenses granted to the Company, and protection of proprietary technology. If the Company does not successfully commercialize or partner any of its product candidates, it will be unable to generate product revenue or achieve profitability.
Segments	Segments Operating segments are identified as components of an enterprise about which separate discrete financial information is available for evaluation by the chief operating decision-maker in making decisions regarding resource allocation and assessing performance. The Company views its operations and manages its business in one operating segment, that of the development of and commercialization of novel immuno-oncology therapies that are designed to harness the immune system to attack cancer cells.
Critical Accounting Policies	Critical Accounting Policies The Company’s critical accounting policies are described in Note 2 to our consolidated financial statements for the year ended December 31, 2016, included in our Annual Report on Form 10-K. There have been no material changes to the Company’s critical accounting policies during the three months ended March 31, 2017.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2014-09, Revenue from Contracts with Customers, which required an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. ASU No. 2014-09 will replace most existing revenue recognition guidance in U.S. GAAP when it becomes effective. The new standard is effective January 1, 2018 for public companies. Early application is permitted as of January 1, 2017. The standard permits the use of either the retrospective or cumulative effect transition method. In March 2016, the FASB issued ASU No. 2016-08, Revenue from Contracts with Customers (Topic 606): Principal versus Agent Considerations (Reporting Revenue Gross versus Net), which clarifies the implementation guidance on principal versus agent considerations in ASU No. 2014-09. In April 2016, the FASB issued ASU No. 2016-10, Revenue from Contracts with Customers (Topic 606): Identifying Performance Obligations and Licensing, which clarifies certain aspects of identifying performance obligations and licensing implementation guidance. In May 2016, the FASB issued ASU No. 2016-12, Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients, which relates to disclosures of remaining performance obligations, as well as other amendments to guidance on collectability, non-cash consideration and the presentation of sales and other similar taxes collected from customers. These standards have the same effective date and transition date of January 1, 2018. The Company does not believe adopting this guidance will have a material impact on its consolidated financial statements as the Company is not yet generating revenues. In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) that replaces existing lease guidance. The new standard requires lessees to record right of use assets and corresponding lease liabilities on the balance sheet. The new guidance will continue to classify leases as either finance or operating, with classification affecting the pattern of expense recognition in the statement of income. The standard is effective for the Company beginning January 1, 2019, with early application permitted. The new standard is required to be applied with a modified retrospective approach to each prior reporting period presented with various optional practical expedients. The Company is currently assessing the impact of this guidance on its consolidated financial statements.

Net Loss per Share (Tables)

3 Months Ended

Mar. 31, 2017

Net Loss per Share

Schedule of net loss per share, basic and diluted

The following table shows the calculation of net loss per share (in thousands, except share and per share data):

	Three Months Ended
	March 31,
	2017			2016
Numerator:
Net loss - basic and diluted	$	(16,036	)	$	(6,347	)

Denominator:
Weighted average common shares outstanding	20,929,110			2,057,200
Less: weighted average common shares subject to repurchase	(579,719		)	(880,654		)

Weighted average common shares outstanding used to compute basic and diluted net loss per share	20,349,391			1,176,546

Net loss per share, basic and diluted	$	(0.79	)	$	(5.39	)

Schedule of antidilutive securities excluded from calculation of diluted net loss per share

	March 31,
	2017	2016
Common stock subject to repurchase	538,575	840,235
Outstanding options	2,358,272	1,787,386

Total shares of common stock equivalents	2,896,847	2,627,621

Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2017

Fair Value Measurements

Schedule of fair value of assets and liabilities recorded at fair value on a recurring basis, by level within fair value hierarchy

	March 31, 2017
	Fair Value Measured Using						Total
	(Level 1)		(Level 2)		(Level 3)		Balance
Assets
Cash equivalents	$	8,436	$	—	$	—	$	8,436
Marketable securities	111,577		—		—		111,577

	$	120,013	$	—	$	—	$	120,013

	December 31, 2016
	Fair Value Measured Using						Total
	(Level 1)		(Level 2)		(Level 3)		Balance
Assets
Cash equivalents	$	2,999	$	—	$	—	$	2,999
Marketable securities	129,846		—		—		129,846

	$	132,845	$	—	$	—	$	132,845

Schedule of fair value of available for sale marketable securities

As of March 31, 2017 and December 31, 2016, the fair value of available for sale marketable securities by type of security were as follows (in thousands):

	March 31, 2017
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
U.S. Treasury securities	$	111,639	$	—	$	(62	)	$	111,577

	December 31, 2016
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
U.S. Treasury securities	$	129,885	$	—	$	(39	)	$	129,846

Balance Sheet Components (Tables)

3 Months Ended

Mar. 31, 2017

Balance Sheet Components

Schedule of prepaid and other current assets

	March 31,		December 31,
	2017		2016
Prepaid and Other Current Assets
Interest receivable	$	53	$	365
Prepaid research and development manufacturing expenses	170		—
Other	828		772

	$	1,051	$	1,137

Schedule of property and equipment, net

Property and Equipment, net
Laboratory equipment	$	1,933		$	1,868
Computer equipment and purchased software	66			58
Leasehold improvements	2,051			2,051

	4,050			3,977
Less: accumulated depreciation and amortization	(933		)	(729		)

	$	3,117		$	3,248

Schedule of accrued and other liabilities

Accrued and Other Liabilities
Accrued clinical trial related	$	2,126	$	1,617
Accrued manufacturing expense	1,416		955
Personnel related	660		526
Deferred rent	386		378
Accrued legal and accounting	309		255
Other accrued expenses	261		313

	$	5,158	$	4,044

Schedule of other liabilities

Other Liabilities
Deferred rent	$	1,269	$	1,370
Shares subject to vesting	28		35

	$	1,297	$	1,405

Common Stock (Tables)

3 Months Ended

Mar. 31, 2017

Common Stock

Schedule of shares of common stock reserved for issuance, on an as-converted basis

	March 31,	December 31,
	2017	2016
Shares available for future option grants	3,285,824	2,475,600
Outstanding options	2,358,272	2,350,582
Unvested restricted common stock (founders and early exercise of stock options)	538,575	611,698
Shares reserved for employee stock purchase plan	400,000	200,000

Total	6,582,671	5,637,880

Stock Option Plans (Tables)

3 Months Ended

Mar. 31, 2017

Stock Option Plans

Summary of stock option activity

			Options Outstanding
					Weighted-
	Shares				Average
	Available		Number		Exercise
	for Grant		of Options		Price
Balance at December 31, 2016	2,475,600		2,350,582		$	11.88
Additional shares authorized	830,000		—		—
Options granted	(58,000	)	58,000		15.29
Options exercised	—		(12,086	)	0.64
Options forfeited	38,224		(38,224	)	9.56

Balance at March 31, 2017	3,285,824		2,358,272		$	12.06

Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2017

Stock-Based Compensation

Schedule of expenses relating to employee and non-employee stock-based awards

The Company’s results of operations include expenses relating to employee and non-employee stock-based awards as follows (in thousands):

	Three Months Ended
	March 31,
	2017		2016
Research and development	$	623	$	301
General and administrative	845		140

Total	$	1,468	$	441

Commitments and Contingencies (Tables)

3 Months Ended

Mar. 31, 2017

Commitments and Contingencies

Schedule of future minimum lease payments under the facility lease

As of March 31, 2017, future minimum lease payments under the facility lease were as follows (in thousands):

Year Ended December 31:
2017 *	$	836
2018	1,143
2019	1,177
2020	1,211
2021	101

Total	$	4,468

*Remainder of the year

Organization - IPO (Details) - USD ($) $ / shares in Units, $ in Millions	Apr. 26, 2016	Mar. 29, 2016
IPO
Initial Public Offering
Share Price		$ 15.00
Issuance of stock (in shares)		4,700,000
Net proceeds from IPO		$ 70.6
Over-Allotment Option
Initial Public Offering
Share Price	$ 15.00
Issuance of stock (in shares)	502,618

Summary of Significant Accounting Policies - Basis of presentation and credit risk (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2017 USD ($) segment item	Mar. 31, 2016 USD ($)	Dec. 31, 2016 USD ($)
Summary of Significant Accounting Policies
Net loss	$ (16,036)	$ (6,347)
Cash in operations	(12,748)	(5,636)
Accumulated deficit	(83,907)		$ (67,871)
Cash, cash equivalents and marketable securities	$ 122,100
Concentrations of Credit Risk and Other Risks and Uncertainties
Number of highly credit qualified financial institutions \| item	2
Net loss	$ (16,036)	(6,347)
Cash in operations	$ (12,748)	$ (5,636)
Segments
Number of operating segments \| segment	1

- Definition

Cash includes currency on hand as well as demand deposits with banks or financial institutions. It also includes other kinds of accounts that have the general characteristics of demand deposits in that the customer may deposit additional funds at any time and effectively may withdraw funds at any time without prior notice or penalty. Cash equivalents, excluding items classified as marketable securities, include short-term, highly liquid Investments that are both readily convertible to known amounts of cash, and so near their maturity that they present minimal risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three years ago does not become a cash equivalent when its remaining maturity is three months. Short-term investments, exclusive of cash equivalents, generally consist of marketable securities intended to be sold within one year (or the normal operating cycle if longer) and may include trading securities, available-for-sale securities, or held-to-maturity securities (if maturing within one year), as applicable.

+ References + Details

Net Loss per Share - Net Loss Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Numerator:
Net loss-basic and diluted	$ (16,036)	$ (6,347)
Denominator:
Weighted average common shares outstanding	20,929,110	2,057,200
Less: weighted average common shares subject to repurchase	(579,719)	(880,654)
Weighted average common shares used to compute basic and diluted net loss per share	20,349,391	1,176,546
Net loss per share, basic and diluted (in dollars per share)	$ (0.79)	$ (5.39)

Net Loss per Share - Anti-Dilutive Securities (Details) - shares	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Excluded from the calculation of diluted net loss per share, due to anti-dilutive effect
Shares of common stock equivalents	2,896,847	2,627,621
Common stock subject to repurchase
Excluded from the calculation of diluted net loss per share, due to anti-dilutive effect
Shares of common stock equivalents	538,575	840,235
Outstanding options
Excluded from the calculation of diluted net loss per share, due to anti-dilutive effect
Shares of common stock equivalents	2,358,272	1,787,386

Fair Value Measurements - Recurring (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Transfer between levels
Transfer of assets from level 1 to 2	$ 0
Transfer of assets from level 2 to 1	0
Transfer of liabilities from level 1 to 2	0
Transfer of liabilities from level 2 to 1	0
Assets
Marketable securities	111,577	$ 129,846
U.S. Treasury securities
Assets
Marketable securities	$ 111,577	129,846
Maximum remaining maturity of marketable securities	8 months
Recurring
Assets
Cash equivalents	$ 8,436	2,999
Marketable securities	111,577	129,846
Total Assets	120,013	132,845
Recurring \| Level 1
Assets
Cash equivalents	8,436	2,999
Marketable securities	111,577	129,846
Total Assets	$ 120,013	$ 132,845

Fair Value Measurements - Available For Sale (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Fair value of available for sale marketable securities
Fair Value	$ 111,577	$ 129,846
U.S. Treasury securities
Fair value of available for sale marketable securities
Amortized Cost	111,639	129,885
Gross Unrealized Losses	(62)	(39)
Fair Value	$ 111,577	$ 129,846

License and Collaboration Agreements (Details) - Licensing Agreement - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2015	Feb. 28, 2017
Scripps Research Institute
License and Collaboration Agreements
Minimum annual fee		$ 25,000
Aggregate potential milestone payments	$ 2,600,000
Milestone payments made	$ 0
Period of written notice to terminate	90 days
Scripps Research Institute \| Research and development
License and Collaboration Agreements
One-time cash payment		$ 10,000
Vernalis (R&D) Limited
License and Collaboration Agreements
Milestone payments made			$ 3,000,000
Period of written notice to terminate	90 days
Vernalis (R&D) Limited \| Minimum
License and Collaboration Agreements
Aggregate potential milestone payments	$ 200,000,000
Vernalis (R&D) Limited \| Research and development
License and Collaboration Agreements
One-time cash payment	$ 1,000,000

Balance Sheet Components - Prepaid and Other Current Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Prepaid and Other Current Assets
Interest Receivable	$ 53	$ 365
Prepaid research and development manufacturing expenses	170
Other	828	772
Total of prepaid and other current assets	$ 1,051	$ 1,137

Balance Sheet Components - Property and Equipment (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Property and Equipment, net
Property and equipment, gross	$ 4,050	$ 3,977
Less: accumulated depreciation and amortization	(933)	(729)
Property and equipment, net	3,117	3,248
Laboratory equipment
Property and Equipment, net
Property and equipment, gross	1,933	1,868
Computer equipment and purchased software
Property and Equipment, net
Property and equipment, gross	66	58
Leasehold improvements
Property and Equipment, net
Property and equipment, gross	$ 2,051	$ 2,051

Balance Sheet Components - Accrued and Other Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Accrued and Other Liabilities
Accrued clinical trial related	$ 2,126	$ 1,617
Accrued Manufacturing Expense	1,416	955
Personnel related	660	526
Deferred rent	386	378
Accrued legal and accounting	309	255
Other accrued expenses	261	313
Accrued Liabilities and Other Liabilities, Total	$ 5,158	$ 4,044

Balance Sheet Components - Other Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Other Liabilities
Deferred rent	$ 1,269	$ 1,370
Shares subject to vesting	28	35
Total of other liabilities	$ 1,297	$ 1,405

Common Stock (Details)	3 Months Ended
Common Stock (Details)	Mar. 31, 2017 USD ($) Vote shares	Mar. 31, 2016 USD ($)	Dec. 31, 2016 shares
Common Stock
Common stock, shares authorized for issuance	290,000,000		290,000,000
Preferred stock, shares authorized for issuance	10,000,000		10,000,000
Number of votes per share of common stock \| Vote	1
Dividends on common stock \| $	$ 0
Proceeds from sale of common stock to founders \| $		$ 64,343,000
Shares of common stock reserved for issuance, on an as-converted basis
Shares available for future option grants	3,285,824		2,475,600
Outstanding options	2,358,272		2,350,582
Unvested restricted common stock (founders and early exercise of stock options)	538,575		611,698
Shares reserved for employee stock purchase plan	400,000		200,000
Total	6,582,671		5,637,880

Stock Option Plans - Stock Option Activity (Details) - $ / shares	1 Months Ended		3 Months Ended
	Mar. 31, 2016	Feb. 28, 2014	Mar. 31, 2017
Shares Available for Grant
Beginning balance			2,475,600
Ending balance			3,285,824
Number of Options
Beginning balance			2,350,582
Ending balance			2,358,272
2016 Plan
Stock Option Plans
Vesting period	4 years
Maximum exercise term	10 years
Exercise price of common stock of its fair value (as a percent)	100.00%
Shares Available for Grant
Beginning balance			2,475,600
Shares authorized for plan			830,000
Granted			(58,000)
Forfeited			38,224
Ending balance			3,285,824
Number of Options
Beginning balance			2,350,582
Granted			58,000
Exercised			(12,086)
Forfeited			(38,224)
Ending balance			2,358,272
Weighted Average Exercise Price
Beginning balance (in dollars per share)			$ 11.88
Granted (in dollars per share)			15.29
Exercised (in dollars per share)			0.64
Forfeited (in dollars per share)			9.56
Ending balance (in dollars per share)			$ 12.06
2014 Plan
Stock Option Plans
Vesting period		4 years
Maximum exercise term		10 years
Exercise price of common stock of its fair value (as a percent)		100.00%
Maximum number of options that may be re-issued under the 2016 plan	1,136,229

Stock-Based Compensation - Expense Allocation (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Stock-based compensation
Stock-based compensation expense	$ 1,468	$ 441
Research and development
Stock-based compensation
Stock-based compensation expense	623	301
General and administrative
Stock-based compensation
Stock-based compensation expense	$ 845	$ 140

Commitments and Contingencies (Details)	1 Months Ended		3 Months Ended
Commitments and Contingencies (Details)	Aug. 31, 2016 ft²	Jan. 31, 2015 ft²	Mar. 31, 2017 USD ($)	Mar. 31, 2016 USD ($)
Facility Lease
Landlord Provided Free Rent And Lease Incentives			$ 1,900,000
Rent expense			184,000	$ 129,000
Operating lease obligations
2017			836,000
2018			1,143,000
2019			1,177,000
2020			1,211,000
2021			101,000
Total			$ 4,468,000
Facilities lease \| Office and laboratory space in Burlingame, California
Facility Lease
Area of leased facility \| ft²		8,138
Additional area of lease \| ft²	28,633
Lease term		1 year
Lease agreement, right to extend the term			3 years

Commitments and Contingencies - Line of Credit (Details) $ in Millions	Aug. 31, 2015 USD ($)
Line of credit
Security deposit	$ 0.1
Secured debt
Line of credit
Line of credit	$ 0.1

Organization (Details)	3 Months Ended
Organization (Details)	Mar. 31, 2017 subsidiary
Organization
Number of insignificant subsidiaries	4

Subsequent Event (Details)	May 01, 2017 item
Subsequent Event
Subsequent Event
Maximum number of patients in treatment arm under collaboration agreement	65