Condensed Consolidated Statement of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income	Accumulated Deficit
Beginning balance at Dec. 31, 2019	$ 194,743	$ 7	$ 414,414	$ 142	$ (219,820)
Beginning balance (in shares) at Dec. 31, 2019		69,052,873
Issuance of common stock upon follow-on public offering, net of issuance costs	224,511	$ 1	224,510
Issuance of common stock upon follow-on public offering, net of issuance costs (in shares)		9,602,500
Exercise of stock options	3,217		3,217
Exercise of stock options (in shares)		361,096
Stock-based compensation	6,642		6,642
Unrealized gain (loss) on marketable securities	2,640			2,640
Net loss	(40,019)				(40,019)
Ending balance at Mar. 31, 2020	391,734	$ 8	648,783	2,782	(259,839)
Ending balance (in shares) at Mar. 31, 2020		79,016,469
Beginning balance at Dec. 31, 2020	$ 267,530	$ 8	676,956	614	(410,048)
Beginning balance (in shares) at Dec. 31, 2020	79,316,261	79,316,261
Exercise of stock options	$ 3,874		3,874
Exercise of stock options (in shares)		415,386
Stock-based compensation	8,800		8,800
Unrealized gain (loss) on marketable securities	(204)			(204)
Net loss	(52,171)				(52,171)
Ending balance at Mar. 31, 2021	$ 227,829	$ 8	$ 689,630	$ 410	$ (462,219)
Ending balance (in shares) at Mar. 31, 2021	79,731,647	79,731,647