Warrants

6 Months Ended

Jun. 30, 2021

Equity [Abstract]

Warrants

Warrants

As of June 30, 2021, the following warrants for common stock were issued and outstanding:

Issue date	Expiration date	Exercise price		Number of warrants outstanding
January 11, 2017	None	$	0.001	3,578,036
November 20, 2017	None	$	0.001	3,669,360
June 11, 2018	None	$	0.001	358,415
				7,605,811

During the three months ended June 30, 2021, no warrants were exercised. During the six months ended June 30, 2021, 623,821 warrants for shares of the Company’s common stock were exercised via cashless exercise, resulting in the issuance of 623,814 shares of common stock. During the three and six months ended June 30, 2020, 600,006 warrants for shares of the Company’s common stock were exercised via cashless exercise, resulting in the issuance of 600,000 shares of common stock.

Shareholders’ Equity

Sale of Common Stock    

In October 2020, the Company sold 4,585,706 shares of its common stock at a public offering price of $202.00 per share. After deducting underwriter discounts, commissions and estimated offering expenses, the Company received net proceeds from the transaction of $879.6 million.

In January 2020, the Company sold 3,538,462 shares of its common stock at a public offering price of $97.50 per share. After deducting underwriter discounts, commissions and offering expenses, the Company received net proceeds from the transaction of $324.0 million.

At the Market Facility

On July 2, 2020, the Company entered into a sales agreement pursuant to which the Company may, from time to time, sell shares of the Company’s common stock, par value $0.001 per share, having an aggregate offering price of up to $200.0 million. As of June 30, 2021, the Company has not offered or sold any shares of common stock pursuant to this sales agreement. See Note 11 - Subsequent Event.

Share-based Compensation

Total share-based compensation expense by statement of operations and comprehensive loss classification is presented below (in thousands):

	Three Months Ended June 30,				Six Months Ended June 30,
	2021		2020		2021		2020
Research and development expense	$	16,469	$	11,457	$	31,003	$	23,305
General and administrative expense	11,500		9,330		21,688		19,049
	$	27,969	$	20,787	$	52,691	$	42,354

During the three and six months ended June 30, 2021, 224,129 and 537,032 shares of common stock were issued under the Company’s equity incentive plans, generating net proceeds of $6.6 million and $16.5 million, respectively. During the three and six months ended June 30, 2020, 323,789 and 820,310 shares of common stock were issued under the Company’s equity incentive plans, generating net proceeds of $8.7 million and $23.9 million, respectively.