Kodiak Sciences (KOD) 10-Q 9 Aug 21 2021 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2021	Jul. 31, 2021
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2
Trading Symbol	KOD
Entity Registrant Name	KODIAK SCIENCES INC.
Entity Central Index Key	0001468748
Entity Current Reporting Status	Yes
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Shell Company	false
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		51,451,541
Entity File Number	001-38682
Entity Tax Identification Number	27-0476525
Entity Address, Address Line One	1200 Page Mill Road
Entity Address, City or Town	Palo Alto
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94304
City Area Code	650
Local Phone Number	281-0850
Entity Interactive Data Current	Yes
Title of 12(b) Security	Common stock, par value $0.0001
Security Exchange Name	NASDAQ
Entity Incorporation, State or Country Code	DE
Document Quarterly Report	true
Document Transition Report	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (unaudited) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 880,870	$ 944,396
Marketable securities	0	24,578
Prepaid expenses and other current assets	3,462	3,031
Total current assets	884,332	972,005
Restricted cash	6,324	6,324
Property and equipment, net	9,460	5,136
Operating lease right-of-use asset	70,278	73,672
Other assets	27,207	10,210
Total assets	997,601	1,067,347
Current liabilities:
Accounts payable	2,738	8,646
Accrued and other current liabilities	37,034	20,402
Operating lease liability	1,248	2,374
Total current liabilities	41,020	31,422
Operating lease liability, net of current portion	77,004	75,028
Liability related to sale of future royalties	99,916	99,890
Other liabilities	234	256
Total liabilities	218,174	206,596
Commitments and contingencies (Note 6)
Stockholders’ equity:
Preferred stock, $0.0001 par value, 10,000,000 shares authorized; 0 shares issued and outstanding at June 30, 2021 and December 31, 2020, respectively
Common stock, $0.0001 par value, 490,000,000 shares authorized at June 30, 2021 and December 31, 2020; 51,434,408 and 51,112,302 shares issued and outstanding at June 30, 2021 and December 31, 2020, respectively	5	5
Additional paid-in capital	1,176,948	1,151,920
Accumulated other comprehensive income	0	53
Accumulated deficit	(397,526)	(291,227)
Total stockholders’ equity	779,427	860,751
Total liabilities and stockholders’ equity	$ 997,601	$ 1,067,347

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) (unaudited) - $ / shares	Jun. 30, 2021	Dec. 31, 2020
Statement Of Financial Position [Abstract]
Preferred stock, par value	$ 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	$ 0.0001	$ 0.0001
Common stock, shares authorized	490,000,000	490,000,000
Common stock, shares issued	51,434,408	51,112,302
Common stock, shares outstanding	51,434,408	51,112,302

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss (unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Operating expenses
Research and development	$ 45,404	$ 20,557	$ 85,741	$ 40,727
General and administrative	10,505	6,222	20,726	11,775
Total operating expenses	55,909	26,779	106,467	52,502
Loss from operations	(55,909)	(26,779)	(106,467)	(52,502)
Interest income	81	698	230	1,906
Interest expense	(5)	(6)	(11)	(13)
Other income (expense), net	(19)	88	(51)	218
Net loss	$ (55,852)	$ (25,999)	$ (106,299)	$ (50,391)
Net loss per common share, basic and diluted	$ (1.08)	$ (0.58)	$ (2.06)	$ (1.12)
Weighted-average common shares outstanding used in computing net loss per common share, basic and diluted	51,573,894	44,969,795	51,644,946	44,897,269
Other comprehensive income (loss)
Change in unrealized gains related to available-for-sale debt securities, net of tax	$ (18)	$ 105	$ (53)	$ 584
Total other comprehensive income (loss)	(18)	105	(53)	584
Comprehensive loss	$ (55,870)	$ (25,894)	$ (106,352)	$ (49,807)

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning Balance at Dec. 31, 2019	$ 345,359	$ 5	$ 503,475	$ 10	$ (158,131)
Beginning balance, shares at Dec. 31, 2019		44,413,404
Issuance of common stock upon exercise of stock options	159		159
Issuance of common stock upon exercise of stock options, shares		39,297
Stock-based compensation expense	6,082		6,082
Other comprehensive income (loss)	479			479
Net loss	(24,392)				(24,392)
Ending Balance at Mar. 31, 2020	327,687	$ 5	509,716	489	(182,523)
Ending balance, shares at Mar. 31, 2020		44,452,701
Beginning Balance at Dec. 31, 2019	345,359	$ 5	503,475	10	(158,131)
Beginning balance, shares at Dec. 31, 2019		44,413,404
Other comprehensive income (loss)	584
Net loss	(50,391)
Ending Balance at Jun. 30, 2020	309,197	$ 5	517,120	594	(208,522)
Ending balance, shares at Jun. 30, 2020		44,667,016
Beginning Balance at Mar. 31, 2020	327,687	$ 5	509,716	489	(182,523)
Beginning balance, shares at Mar. 31, 2020		44,452,701
Issuance of common stock upon exercise of stock options	720		720
Issuance of common stock upon exercise of stock options, shares		203,373
Issuance of common stock upon vesting of restricted stock units, net of taxes withheld	(206)		(206)
Issuance of common stock upon vesting of restricted stock units, net of taxes withheld, shares		10,942
Stock-based compensation expense	6,890		6,890
Other comprehensive income (loss)	105			105
Net loss	(25,999)				(25,999)
Ending Balance at Jun. 30, 2020	309,197	$ 5	517,120	594	(208,522)
Ending balance, shares at Jun. 30, 2020		44,667,016
Beginning Balance at Dec. 31, 2020	860,751	$ 5	1,151,920	53	(291,227)
Beginning balance, shares at Dec. 31, 2020		51,112,302
Issuance of common stock upon exercise of stock options	1,483		1,483
Issuance of common stock upon exercise of stock options, shares		113,559
Stock-based compensation expense	9,925		9,925
Other comprehensive income (loss)	(35)			(35)
Net loss	(50,447)				(50,447)
Ending Balance at Mar. 31, 2021	821,677	$ 5	1,163,328	18	(341,674)
Ending balance, shares at Mar. 31, 2021		51,225,861
Beginning Balance at Dec. 31, 2020	860,751	$ 5	1,151,920	53	(291,227)
Beginning balance, shares at Dec. 31, 2020		51,112,302
Other comprehensive income (loss)	(53)
Net loss	(106,299)
Ending Balance at Jun. 30, 2021	779,427	$ 5	1,176,948	0	(397,526)
Ending balance, shares at Jun. 30, 2021		51,434,408
Beginning Balance at Mar. 31, 2021	821,677	$ 5	1,163,328	18	(341,674)
Beginning balance, shares at Mar. 31, 2021		51,225,861
Issuance of common stock upon exercise of stock options	2,228		2,228
Issuance of common stock upon exercise of stock options, shares		131,276
Issuance of common stock upon vesting of restricted stock units, net of taxes withheld, shares		72,976
Issuance of common stock pursuant to employee stock purchase plans	305		305
Issuance of common stock pursuant to employee stock purchase plans, shares		4,295
Stock-based compensation expense	11,087		11,087
Other comprehensive income (loss)	(18)			(18)
Net loss	(55,852)				(55,852)
Ending Balance at Jun. 30, 2021	$ 779,427	$ 5	$ 1,176,948	$ 0	$ (397,526)
Ending balance, shares at Jun. 30, 2021		51,434,408

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Cash flows from operating activities
Net loss	$ (106,299)	$ (50,391)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	466	216
Stock-based compensation	21,012	12,972
Amortization (accretion) of premium (discount) on marketable securities	(25)	231
Amortization of operating lease right-of-use asset	3,897	199
Amortization of issuance costs	26	22
Changes in assets and liabilities:
Prepaid expenses and other current assets	431	(933)
Other assets	35	2,305
Accounts payable	(5,753)	4,338
Accrued and other current liabilities	15,459	2,620
Operating lease liability	347	(210)
Net cash used in operating activities	(71,286)	(31,837)
Cash flows from investing activities
Purchase of property and equipment	(3,772)	(249)
Deposits on property and equipment	16,962	0
Purchase of marketable securities	0	(86,317)
Maturities of marketable securities	24,500	76,150
Net cash provided by (used in) investing activities	3,766	(10,416)
Cash flows from financing activities
Proceeds from issuance of common stock pursuant to employee stock purchase plans	305	0
Payments for restricted stock units, net of taxes withheld	0	(206)
Proceeds from issuance of common stock upon options exercise	3,711	879
Proceeds from sale of future royalties, net of issuance costs	0	99,643
Principal payments of capital lease	0	(5)
Principal payments of tenant improvement allowance payable	22	19
Net cash provided by financing activities	3,994	100,292
Net increase (decrease) in cash, cash equivalents and restricted cash	(63,526)	58,039
Cash, cash equivalents and restricted cash, at beginning of period	950,720	211,937
Cash, cash equivalents and restricted cash, at end of period	887,194	269,976
Reconciliation of cash, cash equivalents and restricted cash to consolidated balance sheets
Cash and cash equivalents	880,870	269,836
Restricted cash	6,324	140
Cash, cash equivalents and restricted cash, at end of period	887,194	269,976
Supplemental disclosures of non-cash investing and financing information:
Operating lease right-of-use asset obtained in exchange for operating lease liability	498	0
Purchase of property and equipment under accounts payable and accruals	$ 1,821	$ 77

The Company

The Company	6 Months Ended
	Jun. 30, 2021
Organization Consolidation And Presentation Of Financial Statements [Abstract]
The Company	1. The Company Kodiak Sciences Inc. (the “Company”) is a biopharmaceutical company committed to researching, developing and commercializing transformative therapeutics to treat high prevalence retinal diseases in the United States and additional international markets. The Company devotes substantially all of its resources to the research and development of its product platforms and product candidates including activities to conduct clinical studies of its product candidates, manufacture product candidates and provide general and administrative support for these operations. Liquidity As of June 30, 2021, the Company had cash and cash equivalents of $ 880.9 million. Although the Company has incurred significant operating losses since inception and expects to continue to incur operating losses and negative operating cash flows for the foreseeable future, the Company believes that the cash and cash equivalents will be sufficient to meet the anticipated operating and capital expenditure requirements for the 12 months following the date of this Form 10-Q.

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation and Principles of Consolidation The accompanying condensed consolidated financial statements are unaudited and have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) applicable to interim periods. The condensed consolidated financial statements, in the opinion of management, include all normal and recurring adjustments necessary to present fairly the Company's financial position and results of operations for the reported periods. These condensed consolidated financial statements have been prepared on a basis substantially consistent with, and should be read in conjunction with the audited financial statements for the year ended December 31, 2020 and notes thereto, the Company’s Annual Report on Form 10-K filed with the Securities and Exchange Commission (“SEC”) on March 1, 2021. Certain information and note disclosures normally included in the audited financial statements prepared in accordance with GAAP have been condensed or omitted from this report. The results of operations for any interim period are not necessarily indicative of the results for the year ending December 31, 2021, or for any future period. The accompanying condensed consolidated financial statements reflect the operations of the Company and its wholly-owned subsidiaries. All intercompany accounts and transactions have been eliminated. Reclassification Certain prior period amounts have been reclassified to conform to the current period presentation. Such reclassifications had no impact on subtotals in the prior year condensed consolidated financial statements. Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities as of the date of the condensed consolidated financial statements and expenses during the reporting period. The impact of the ongoing COVID-19 pandemic continues to evolve. As a result, certain estimates and assumptions required increased judgment and carried a higher degree of variability and volatility, including but not limited to, the fair value of marketable securities, performance-based equity awards, and research and development accruals for the three and six months ended June 30, 2021. As events continue to unfold and additional information becomes available, these estimates may change materially in future periods. Actual results could differ from those estimates. Risks and Uncertainties In March 2020, the World Health Organization declared a pandemic due to the global COVID-19 outbreak. The significant uncertainties caused by the ongoing COVID-19 pandemic may negatively impact the Company’s operations, liquidity, and capital resources and will depend on certain evolving developments, including the duration and spread of the outbreak, regulatory and private sector responses and the impact on employees and vendors including supply chain and clinical partners, all of which are uncertain and cannot be predicted. During this pandemic, the Company continues to work closely with clinical sites towards maximal patient safety and the lowest number of missed visits and study discontinuations. The Company has taken and continues to take proactive measures to maintain the integrity of its ongoing clinical studies. Despite these efforts, the ongoing COVID-19 pandemic could significantly impact clinical trial enrollment and completion of its clinical studies. During this pandemic, we continue to work closely with our manufacturing suppliers, partners and facilities to maintain the supply of our product candidates needed for the expansion of our clinical trials and to retain the number, scale and design of manufacturing runs that regulatory authorities may require to obtain marketing approval, including those required to support a BLA submission. Despite these efforts, the ongoing COVID-19 pandemic could significantly impact the timing or likelihood of clinical resupply and of regulatory filings and approvals. The Company will continue to monitor the COVID-19 situation and its impact on the ability to continue the development of, and seek regulatory approvals for, the Company’s product candidates, and begin to commercialize any approved products. Summary of Significant Accounting Policies The significant accounting policies used in preparation of these condensed consolidated financial statements for the three and six months ended June 30, 2021, respectively, are consistent with those discussed in Note 2 to the consolidated financial statements in the Company’s Annual Report on Form 10-K for the year ended December 31, 2020, except as noted within the “Recent Accounting Pronouncements – Recently Adopted Accounting Pronouncements” section. Recent a ccounting p ronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board (“FASB”), under its Accounting Standards Codification or other standard setting bodies, and adopted by the Company as of the specified effective date, unless otherwise discussed below. Recently Adopted Accounting Pronouncements In October 2020, the FASB issued ASU 2020-10, Codification Improvements , which updates various codification topics and disclosure requirements to improve alignment with the SEC's regulations. The Company adopted this new guidance as of January 1, 2021, and this guidance did not have a material impact on its consolidated financial statements and related disclosures. New Accounting Pronouncements Not Yet Adopted The Company continues to monitor new accounting pronouncements issued by the FASB. All other newly issued accounting pronouncements issued through the date of this report have been deemed either immaterial or not applicable.

Accrued and Other Current Liabi

Accrued and Other Current Liabilities	6 Months Ended
	Jun. 30, 2021
Accounts Payable And Accrued Liabilities Current [Abstract]
Accrued and Other Current Liabilities	3. Accrued and Other Current Liabilities Accrued and other current liabilities consist of the following (in thousands): June 30, December 31, Accrued clinical trial and related costs $ 26,398 $ 11,119 Accrued research and development 3,953 3,082 Accrued salaries and benefits 3,425 5,094 Accrued legal fees 707 252 Accrued professional fees 118 253 Accrued other liabilities 2,433 602 Total accrued and other current liabilities $ 37,034 $ 20,402

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurements	4. Fair Value Measurements The following tables present the Company’s fair value hierarchy for assets measured at fair value on a recurring basis (in thousands): Fair Value Measurements at June 30, 2021 Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 825,676 $ — $ — $ 825,676 Total $ 825,676 $ — $ — $ 825,676 Fair Value Measurements at December 31, 2020 Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 917,485 $ — $ — $ 917,485 Marketable securities: U.S. treasury securities — 10,006 — 10,006 Corporate notes — 14,572 — 14,572 Total $ 917,485 $ 24,578 $ — $ 942,063 As of June 30, 2021 and December 31, 2020 , the fair value of the liability related to sale of future royalties is based on our current estimates of future royalties expected to be paid to Baker Bros. Advisors, LP (“BBA”), which are considered Level 3 inputs.

Marketable Securities

Marketable Securities	6 Months Ended
	Jun. 30, 2021
Investments Debt And Equity Securities [Abstract]
Marketable Securities	5. Marketable Securities The marketable securities are classified as available-for-sale and consist of U.S. treasury securities and corporate notes. The fair value measurement data for marketable securities is obtained from independent pricing services. The Company validates the prices provided by the third-party pricing services by understanding the valuation methods and data sources used and analyzing the pricing data in certain instances. The Company had no marketable securities at June 30, 2021 . The following table summarizes the marketable securities (in thousands): As of December 31, 2020 Amortized Unrealized Unrealized Fair U.S. treasury securities $ 10,003 $ 3 $ — $ 10,006 Corporate notes 14,522 50 — 14,572 Total marketable securities, current $ 24,525 $ 53 $ — $ 24,578 All marketable securities held at December 31, 2020 had effective maturities of less than one year . There were no realized gains or losses recognized on the sale or maturity of available-for-sale debt securities during the three and six months ended June 30, 2021, respectively, and as a result, the Company did not reclassify any amounts out of accumulated comprehensive loss. As of June 30, 2021 and December 31, 2020 , the Company had no allowance for credit losses for available-for-sale debt securities. There were no impairment charges or recoveries recorded during each of the six months ended June 30, 2021 and June 30, 2020 , respectively.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2021
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	6. Commitments and Contingencies Embedded Lease In August 2020, the Company and its wholly-owned subsidiary Kodiak Sciences GmbH entered into a manufacturing agreement with Lonza Ltd (“Lonza”) for the clinical and commercial supply of drug substance for KSI-301. A custom-built manufacturing facility is planned to be completed and dedicated to the manufacture of the Company’s drug substance. The manufacturing agreement has an initial term of eight years , and the Company has the right to extend the term up to a total of 16 years . The Company and Lonza each have the ability to terminate this agreement upon the occurrence of certain conditions. In April 2021, the agreement was amended to provide for higher annual manufacturing capacity. The Company expanded and finalized the design and scope of the bioconjugate manufacturing facility with a revised estimated capital contribution of approximately 75.0 million Swiss Francs. Over the period from 2022 through 2029, manufacturing fees totaling approximately 150.0 million Swiss Francs may be incurred for potential commercial supply of KSI-301 drug substance. The Company concluded that this agreement contains an embedded lease as the custom-built manufacturing suite will be dedicated for the Company’s use. As of June 30, 2021, the Company did not have control of this manufacturing space and therefore, did no t record a right-of-use asset and corresponding lease liability. Manufacturing Agreements The Company has entered into service agreements in the normal course of business with various service providers, pursuant to which such service providers agreed to perform activities in connection with the manufacturing process of certain materials. These agreements, and any related amendments, state that planned activities that are included in the signed work orders are, in some cases, binding and, hence, obligate the Company to pay the full price of the work order upon satisfactory delivery of products and services or obligate the Company to the binding amount regardless of whether such planned activities are in fact performed. Per the terms of the agreements, the Company has the option to cancel signed orders at any time upon written notice, which may or may not be subject to payment of a cancellation fee. The level of cancellation fees may be dependent on the timing of the written notice in relation to the commencement date of the work, with the maximum cancellation amount dependent on the agreement or the work order. Other Funding Commitments In the normal course of business, the Company enters into agreements with third-parties for services to be provided to the Company. Generally, these agreements provide for termination upon notice, with specified amounts due upon termination based on the timing of termination and the terms of the applicable agreement. The actual amounts and timing of payments under these agreements are uncertain and contingent upon the initiation and completion of services to be provided to the Company. The Company has also entered into various cancellable license agreements for certain technology. The Company may be obligated to make payments on future sales of specified products associated with such license agreements. Such payments are dependent on future product sales and are not estimable. Indemnification To the extent permitted under Delaware law, the Company has agreed to indemnify its directors and officers for certain events or occurrences while the director or officer is, or was serving, at the Company’s request in such capacity. The indemnification period covers all pertinent events and occurrences during the director’s or officer’s service. The maximum potential amount of future payments the Company could be required to make under these indemnification agreements is not specified in the agreements; however, the Company has director and officer insurance coverage that reduces its exposure and enables the Company to recover a portion of any future amounts paid. The Company believes the estimated fair value of these indemnification agreements in excess of applicable insurance coverage is minimal.

Stock-Based Compensation

Stock-Based Compensation	6 Months Ended
	Jun. 30, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	7. Stock-Based Compensation In January 2021 and 2020 , the number of shares of common stock available for issuance under the 2018 Equity Incentive Plan (the "2018 Plan") was increased by approximately 2.0 million and 1.8 million shares, respectively, as a result of the automatic increase provision in the 2018 Plan. Stock Options Stock option activity under the 2018 Plan and 2015 Equity Incentive Plan (the "2015 Plan") is summarized as follows: Number Weighted Weighted Aggregate Outstanding at December 31, 2020 6,897,276 $ 24.52 8.07 $ 841,704 Granted 288,689 $ 121.99 Exercised ( 244,835 ) $ 15.15 Forfeited or canceled ( 119,606 ) $ 39.53 Outstanding at June 30, 2021 6,821,524 $ 28.65 7.61 $ 446,963 Restricted Shares Restricted share activity, including restricted stock awards, restricted stock units, and performance-based restricted stock units, under the 2018 Plan and 2015 Plan is summarized as follows: Number of Weighted Unvested at December 31, 2020 359,945 $ 59.54 Granted 21,700 $ 106.76 Vested ( 72,976 ) $ 58.97 Canceled ( 20,307 ) $ 58.00 Unvested at June 30, 2021 288,362 $ 63.34 Performance-Based Stock Options and Restricted Stock Units The Company granted 190,831 performance-based stock options during the six months ended June 30, 2021 (the "2021 PSAs"). The Company did no t grant any performance-based equity awards during 2020 . The Company granted 170,150 performance-based options and 128,900 performance-based restricted stock units to employees in 2019 (the "2019 PSAs"). The performance-based equity awards granted will vest one-quarter upon the achievement of specific clinical development milestones. The remaining shares will then vest ratably over three years thereafter. Performance-based stock options and performance-based restricted stock units are recorded as expense beginning when vesting events are determined to be probable. The milestone for the 2019 PSAs was achieved during the second quarter of 2021. As of June 30, 2021 , 42,536 performance-based stock options and 28,905 performance-based restricted stock units granted during 2019 have vested. The Company believes that the achievement of the requisite performance condition for 2021 PSAs continues to be probable. Stock-based compensation expense recognized was $ 3.7 million and $ 6.2 million during the three and six months ended June 30, 2021 , respectively, and $ 1.8 million and $ 3.6 million during the three and six months ended June 30, 2020, respectively. 2018 Employee Share Purchase Plan In August 2018, the Company adopted the 2018 Employee Share Purchase Plan (“ESPP”), which became effective on the business day prior to the effectiveness of the registration statement relating to the IPO. A total of 460,000 shares of common stock were initially reserved for issuance under the ESPP. The initial offering period of the ESPP was authorized by the Company’s board of directors and commenced on January 4, 2021. Each offering period is approximately twelve months long, with two purchase periods. ESPP participants will purchase shares of common stock at a price per share equal to 85 % of the lesser of (1) the fair market value per share of the common stock on the enrollment date or (2) the fair market value of the common stock on the exercise date. The Company issued 4,295 shares and 4,295 shares under the ESPP during the three and six months ended June 30, 2021 , respectively. The stock-based compensation expense related to the ESPP was $ 0.1 million and $ 0.2 million during the three and six months ended June 30, 2021, respectively. Stock-Based Compensation Expense Stock-based compensation for options, restricted shares, and ESPP is classified in the condensed consolidated statements of operations and comprehensive loss as follows (in thousands): Three Months Ended Six Months Ended 2021 2020 2021 2020 Research and development $ 5,770 $ 3,776 $ 11,169 $ 7,224 General and administrative 5,317 3,114 9,843 5,748 Total stock-based compensation $ 11,087 $ 6,890 $ 21,012 $ 12,972 As of June 30, 2021 , total unrecognized compensation cost related to the unvested share-based awards and ESPP was $ 89.8 million, which is expected to be recognized over a weighted-average period of 2.4 years.

Net Loss per Common Share

Net Loss per Common Share	6 Months Ended
	Jun. 30, 2021
Earnings Per Share [Abstract]
Net Loss per Common Share	8. Net Loss per Common Share The following common share equivalents were excluded from the computation of diluted net loss per common share for the periods presented because their inclusion would have been antidilutive: As of June 30, 2021 2020 Outstanding stock options 6,821,524 7,304,288 Unvested restricted shares 288,362 318,995 Total 7,109,886 7,623,283

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 30, 2021
Subsequent Events [Abstract]
Subsequent Events	9. Subsequent Events Subsequent to June 30, 2021, at the Company's request, Baker Bros. Advisors, LP confirmed in a letter agreement that, despite the Company being in a position to satisfy the product development criteria, the second funding amount would not be paid and the aggregate royalty cap under the Funding Agreement would be reduced from $1,012.5 million to $ 450.0 million. Subsequent to June 30, 2021, the Company has entered into a binding purchase commitment for manufacturing equipment related to the commercial supply of KSI-301. Based on this agreement, the Company is currently committed to minimum non-cancelable purchase obligations of approximately $ 20.0 million, which are expected to be paid through 2023.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2021
Accounting Policies [Abstract]
Basis of Presentation and Principles of Consolidation	Basis of Presentation and Principles of Consolidation The accompanying condensed consolidated financial statements are unaudited and have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) applicable to interim periods. The condensed consolidated financial statements, in the opinion of management, include all normal and recurring adjustments necessary to present fairly the Company's financial position and results of operations for the reported periods. These condensed consolidated financial statements have been prepared on a basis substantially consistent with, and should be read in conjunction with the audited financial statements for the year ended December 31, 2020 and notes thereto, the Company’s Annual Report on Form 10-K filed with the Securities and Exchange Commission (“SEC”) on March 1, 2021. Certain information and note disclosures normally included in the audited financial statements prepared in accordance with GAAP have been condensed or omitted from this report. The results of operations for any interim period are not necessarily indicative of the results for the year ending December 31, 2021, or for any future period. The accompanying condensed consolidated financial statements reflect the operations of the Company and its wholly-owned subsidiaries. All intercompany accounts and transactions have been eliminated.
Reclassification	Reclassification Certain prior period amounts have been reclassified to conform to the current period presentation. Such reclassifications had no impact on subtotals in the prior year condensed consolidated financial statements.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities as of the date of the condensed consolidated financial statements and expenses during the reporting period. The impact of the ongoing COVID-19 pandemic continues to evolve. As a result, certain estimates and assumptions required increased judgment and carried a higher degree of variability and volatility, including but not limited to, the fair value of marketable securities, performance-based equity awards, and research and development accruals for the three and six months ended June 30, 2021. As events continue to unfold and additional information becomes available, these estimates may change materially in future periods. Actual results could differ from those estimates.
Risk and Uncertainties	Risks and Uncertainties In March 2020, the World Health Organization declared a pandemic due to the global COVID-19 outbreak. The significant uncertainties caused by the ongoing COVID-19 pandemic may negatively impact the Company’s operations, liquidity, and capital resources and will depend on certain evolving developments, including the duration and spread of the outbreak, regulatory and private sector responses and the impact on employees and vendors including supply chain and clinical partners, all of which are uncertain and cannot be predicted. During this pandemic, the Company continues to work closely with clinical sites towards maximal patient safety and the lowest number of missed visits and study discontinuations. The Company has taken and continues to take proactive measures to maintain the integrity of its ongoing clinical studies. Despite these efforts, the ongoing COVID-19 pandemic could significantly impact clinical trial enrollment and completion of its clinical studies. During this pandemic, we continue to work closely with our manufacturing suppliers, partners and facilities to maintain the supply of our product candidates needed for the expansion of our clinical trials and to retain the number, scale and design of manufacturing runs that regulatory authorities may require to obtain marketing approval, including those required to support a BLA submission. Despite these efforts, the ongoing COVID-19 pandemic could significantly impact the timing or likelihood of clinical resupply and of regulatory filings and approvals. The Company will continue to monitor the COVID-19 situation and its impact on the ability to continue the development of, and seek regulatory approvals for, the Company’s product candidates, and begin to commercialize any approved products.
Recent Accounting Pronouncements	Recent a ccounting p ronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board (“FASB”), under its Accounting Standards Codification or other standard setting bodies, and adopted by the Company as of the specified effective date, unless otherwise discussed below. Recently Adopted Accounting Pronouncements In October 2020, the FASB issued ASU 2020-10, Codification Improvements , which updates various codification topics and disclosure requirements to improve alignment with the SEC's regulations. The Company adopted this new guidance as of January 1, 2021, and this guidance did not have a material impact on its consolidated financial statements and related disclosures. New Accounting Pronouncements Not Yet Adopted The Company continues to monitor new accounting pronouncements issued by the FASB. All other newly issued accounting pronouncements issued through the date of this report have been deemed either immaterial or not applicable.

Accrued and Other Current Lia_2

Accrued and Other Current Liabilities (Tables)	6 Months Ended
	Jun. 30, 2021
Accounts Payable And Accrued Liabilities Current [Abstract]
Schedule of Accrued and Other Current Liabilities	Accrued and other current liabilities consist of the following (in thousands): June 30, December 31, Accrued clinical trial and related costs $ 26,398 $ 11,119 Accrued research and development 3,953 3,082 Accrued salaries and benefits 3,425 5,094 Accrued legal fees 707 252 Accrued professional fees 118 253 Accrued other liabilities 2,433 602 Total accrued and other current liabilities $ 37,034 $ 20,402

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2021
Fair Value Disclosures [Abstract]
Summary of Fair Value Hierarchy for Assets Measured at Fair Value on Recurring Basis	The following tables present the Company’s fair value hierarchy for assets measured at fair value on a recurring basis (in thousands): Fair Value Measurements at June 30, 2021 Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 825,676 $ — $ — $ 825,676 Total $ 825,676 $ — $ — $ 825,676 Fair Value Measurements at December 31, 2020 Level 1 Level 2 Level 3 Total Cash equivalents: Money market funds $ 917,485 $ — $ — $ 917,485 Marketable securities: U.S. treasury securities — 10,006 — 10,006 Corporate notes — 14,572 — 14,572 Total $ 917,485 $ 24,578 $ — $ 942,063 As of June 30, 2021 and December 31, 2020 , the fair value of the liability related to sale of future royalties is based on our current estimates of future royalties expected to be paid to Baker Bros. Advisors, LP (“BBA”), which are considered Level 3 inputs.

Marketable Securities (Tables)

Marketable Securities (Tables)	6 Months Ended
	Jun. 30, 2021
Investments Debt And Equity Securities [Abstract]
Summary of Marketable Securities	The following table summarizes the marketable securities (in thousands): As of December 31, 2020 Amortized Unrealized Unrealized Fair U.S. treasury securities $ 10,003 $ 3 $ — $ 10,006 Corporate notes 14,522 50 — 14,572 Total marketable securities, current $ 24,525 $ 53 $ — $ 24,578

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Stock Options Activity under 2018 Plan and 2015 Equity Incentive Plan	Stock option activity under the 2018 Plan and 2015 Equity Incentive Plan (the "2015 Plan") is summarized as follows: Number Weighted Weighted Aggregate Outstanding at December 31, 2020 6,897,276 $ 24.52 8.07 $ 841,704 Granted 288,689 $ 121.99 Exercised ( 244,835 ) $ 15.15 Forfeited or canceled ( 119,606 ) $ 39.53 Outstanding at June 30, 2021 6,821,524 $ 28.65 7.61 $ 446,963
Summary of Restricted Shares	Restricted share activity, including restricted stock awards, restricted stock units, and performance-based restricted stock units, under the 2018 Plan and 2015 Plan is summarized as follows: Number of Weighted Unvested at December 31, 2020 359,945 $ 59.54 Granted 21,700 $ 106.76 Vested ( 72,976 ) $ 58.97 Canceled ( 20,307 ) $ 58.00 Unvested at June 30, 2021 288,362 $ 63.34
Summary of Stock-based Compensation for Options and Restricted Shares Classified in Condensed Consolidated Statements of Operations and Comprehensive Loss	Stock-based compensation for options, restricted shares, and ESPP is classified in the condensed consolidated statements of operations and comprehensive loss as follows (in thousands): Three Months Ended Six Months Ended 2021 2020 2021 2020 Research and development $ 5,770 $ 3,776 $ 11,169 $ 7,224 General and administrative 5,317 3,114 9,843 5,748 Total stock-based compensation $ 11,087 $ 6,890 $ 21,012 $ 12,972

Net Loss per Common Share (Tabl

Net Loss per Common Share (Tables)	6 Months Ended
	Jun. 30, 2021
Earnings Per Share [Abstract]
Summary of Anti-dilutive Securities Excluded from Computation of Diluted Net Loss per Common Share	The following common share equivalents were excluded from the computation of diluted net loss per common share for the periods presented because their inclusion would have been antidilutive: As of June 30, 2021 2020 Outstanding stock options 6,821,524 7,304,288 Unvested restricted shares 288,362 318,995 Total 7,109,886 7,623,283

The Company - Additional Inform

The Company - Additional Information (Details) $ in Millions	Jun. 30, 2021USD ($)
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Cash and cash equivalents and marketable securities	$ 880.9

Accrued and Other Current Lia_3

Accrued and Other Current Liabilities - Schedule of Accrued and Other Current Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Accounts Payable And Accrued Liabilities Current [Abstract]
Accrued clinical trial and related costs	$ 26,398	$ 11,119
Accrued research and development	3,953	3,082
Accrued salaries and benefits	3,425	5,094
Accrued legal fees	707	252
Accrued professional fees	118	253
Accrued other liabilities	2,433	602
Total accrued and other current liabilities	$ 37,034	$ 20,402

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Fair Value Hierarchy for Assets Measured at Fair Value on Recurring Basis (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	$ 825,676	$ 942,063
Money Market Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	825,676	917,485
Corporate Notes
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities		14,572
U.S. Treasury Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities		10,006
Quoted Price in Active Markets (Level 1)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total	825,676	917,485
Quoted Price in Active Markets (Level 1) | Money Market Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cash equivalents	$ 825,676	917,485
Significant Observable Inputs (Level 2)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total		24,578
Significant Observable Inputs (Level 2) | Corporate Notes
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities		14,572
Significant Observable Inputs (Level 2) | U.S. Treasury Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Marketable securities		$ 10,006

Marketable Securities - Summary

Marketable Securities - Summary of Marketable Securities (Details) $ in Thousands	Dec. 31, 2020USD ($)
Marketable Securities [Line Items]
Amortized Cost, current	$ 24,525
Unrealized Gains, current	53
Fair Value, current	24,578
U.S. Treasury Securities
Marketable Securities [Line Items]
Amortized Cost, current	10,003
Unrealized Gains, current	3
Fair Value, current	10,006
Corporate Notes
Marketable Securities [Line Items]
Amortized Cost, current	14,522
Unrealized Gains, current	50
Fair Value, current	$ 14,572

Marketable Securities - Additio

Marketable Securities - Additional Information (Details) - USD ($)	3 Months Ended	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Marketable Securities [Line Items]
Availability of Marketable Securities	$ 0	$ 0
Realized gains or losses recognized on sale or maturity of available-for-sale debt securities	0	0
Allowance for credit losses for available-for-sale debt securities	$ 0	0		$ 0
Impairment charges or recoveries related to marketable securities		$ 0	$ 0
Maximum
Marketable Securities [Line Items]
Marketable securities, effective maturities	1 year	1 year		1 year

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) $ in Thousands, SFr in Millions	1 Months Ended
	Aug. 31, 2020	Jun. 30, 2021USD ($)	Apr. 30, 2021CHF (SFr)	Dec. 31, 2020USD ($)
Commitments And Contingencies Disclosure [Line Items]
Operating lease right-of-use asset		$ 70,278		$ 73,672
Lease Agreement
Commitments And Contingencies Disclosure [Line Items]
Operating lease right-of-use asset		0
Lease liabilities		$ 0
Clinical and Commercial Supply of Drug Substance | Manufacturing Agreement | Lonza
Commitments And Contingencies Disclosure [Line Items]
Annual suite fees payment | SFr			SFr 150
Revised estimated capital contribution | SFr			SFr 75
Manufacturing agreement initial term	8 years
Clinical and Commercial Supply of Drug Substance | Maximum | Manufacturing Agreement | Lonza
Commitments And Contingencies Disclosure [Line Items]
Manufacturing agreement term that can be extended	16 years

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Details) $ in Thousands	1 Months Ended		3 Months Ended		6 Months Ended		12 Months Ended
	Jan. 31, 2021shares	Jan. 31, 2020shares	Jun. 30, 2021USD ($)shares	Jun. 30, 2020USD ($)	Jun. 30, 2021USD ($)PurchasePeriodshares	Jun. 30, 2020USD ($)shares	Dec. 31, 2019shares	Dec. 31, 2020shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense recognized | $			$ 11,087	$ 6,890	$ 21,012	$ 12,972
Common stock, shares issued			51,434,408		51,434,408			51,112,302
Stock based compensation expense related to ESPP | $			$ 305
Unrecognized compensation cost related to unvested share based awards | $			89,800		$ 89,800
Unrecognized compensation weighted-average period expected for recognition					2 years 4 months 24 days
Performance Based Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options, granted							128,900
Awards vested					28,905
Performance-based Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options, vested					42,536
Stock options, granted					190,831	0	170,150
Performance Based Equity Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period for achievement of specific milestone					one-quarter
Stock-based compensation expense recognized | $			$ 3,700	$ 1,800	$ 6,200	$ 3,600
2018 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of common stock available for issuance increased	2,000,000	1,800,000
2018 Employee Share Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, shares reserved for issuance			460,000		460,000
Term of offering period					12 months
Number of purchase periods | PurchasePeriod					2
Common stock purchase price percentage					85.00%
Common stock, shares issued			4,295		4,295
Stock based compensation expense related to ESPP | $			$ 100		$ 200

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock Options Activity Under 2018 Plan and 2015 Equity Incentive Plan (Details) - 2018 Plan and 2015 Equity Incentive Plan $ / shares in Units, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2021USD ($)$ / sharesshares	Dec. 31, 2020USD ($)$ / sharesshares
Number of Options
Beginning balance | shares	6,897,276
Granted | shares	288,689
Exercised | shares	(244,835)
Forfeited or canceled | shares	(119,606)
Ending balance | shares	6,821,524	6,897,276
Weighted Average Exercise Price
Beginning balance | $ / shares	$ 24.52
Granted | $ / shares	121.99
Exercised | $ / shares	15.15
Forfeited or canceled | $ / shares	39.53
Ending balance | $ / shares	$ 28.65	$ 24.52
Weighted Average Remaining Contractual Term (in years)
Weighted Average Remaining Contractual Term (in years)	7 years 7 months 9 days	8 years 25 days
Aggregate Intrinsic Value
Balance | $	$ 446,963	$ 841,704

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of Restricted Shares (Details) - Restricted Shares	6 Months Ended
	Jun. 30, 2021$ / sharesshares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vested | shares	(72,976)
Vested | $ / shares	$ 58.97
Number of Restricted Shares
Unvested, beginning balance | shares	359,945
Granted | shares	21,700
Canceled | shares	(20,307)
Unvested, ending balance | shares	288,362
Weighted Average Grant Date Fair Value
Unvested, beginning balance | $ / shares	$ 59.54
Granted | $ / shares	106.76
Canceled | $ / shares	58
Unvested, ending balance | $ / shares	$ 63.34

Stock-Based Compensation - Su_3

Stock-Based Compensation - Summary of Stock-based Compensation for Options and Restricted Shares Classified in Condensed Consolidated Statements of Operations and Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation	$ 11,087	$ 6,890	$ 21,012	$ 12,972
Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation	5,770	3,776	11,169	7,224
General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total stock-based compensation	$ 5,317	$ 3,114	$ 9,843	$ 5,748

Net Loss per Common Share - Sum

Net Loss per Common Share - Summary of Anti-dilutive Securities Excluded from Computation of Diluted Net Loss per Common Share (Details) - shares	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from the computation of diluted net loss per common share	7,109,886	7,623,283
Outstanding Stock Options
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from the computation of diluted net loss per common share	6,821,524	7,304,288
Unvested Restricted Shares
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Anti-dilutive securities excluded from the computation of diluted net loss per common share	288,362	318,995

Subsequent Events - Additional

Subsequent Events - Additional Information (Details) $ in Millions	6 Months Ended
	Jun. 30, 2021USD ($)
Subsequent Event [Line Items]
Minimum Non Cancelable Purchase Obligations To Be Paid Through 2023	$ 20
Baker Bros. Advisors, LP | Minimum | Funding Agreement
Subsequent Event [Line Items]
Contractual obligation under funding agreement	$ 450