Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Deficit
Beginning balance at Dec. 31, 2019	$ 227,955	$ 2	$ 484,372	$ (256,419)
Beginning balance, shares at Dec. 31, 2019		24,728,258
Conversion of Lender Warrants into equity	318		318
Vesting of restricted shares, shares		425,295
Stock-based compensation	563		563
Net loss	(20,141)			(20,141)
Ending balance at Mar. 31, 2020	208,695	$ 2	485,253	(276,560)
Ending balance, shares at Mar. 31, 2020		25,153,553
Beginning balance at Dec. 31, 2019	227,955	$ 2	484,372	(256,419)
Beginning balance, shares at Dec. 31, 2019		24,728,258
Net loss	(41,242)
Ending balance at Jun. 30, 2020	188,423	$ 3	486,081	(297,661)
Ending balance, shares at Jun. 30, 2020		25,614,412
Beginning balance at Mar. 31, 2020	208,695	$ 2	485,253	(276,560)
Beginning balance, shares at Mar. 31, 2020		25,153,553
Vesting of restricted shares	1	$ 1
Vesting of restricted shares, shares		460,859
Stock-based compensation	828		828
Net loss	(21,101)			(21,101)
Ending balance at Jun. 30, 2020	188,423	$ 3	486,081	(297,661)
Ending balance, shares at Jun. 30, 2020		25,614,412
Beginning balance at Dec. 31, 2020	$ 194,271	$ 3	579,755	(385,487)
Beginning balance, shares at Dec. 31, 2020	28,516,010	28,516,010
Issuance of common stock from exercise of stock options	$ 412		412
Issuance of common stock from exercise of stock options, shares		36,998
401(k) matching contribution	323		323
401(k) matching contribution, shares		8,356
Vesting of restricted shares, shares		301,656
Stock-based compensation	3,818		3,818
ESPP shares issued	358		358
ESPP shares issued, shares		13,490
Net loss	(34,843)			(34,843)
Ending balance at Mar. 31, 2021	164,339	$ 3	584,666	(420,330)
Ending balance, shares at Mar. 31, 2021		28,876,510
Beginning balance at Dec. 31, 2020	$ 194,271	$ 3	579,755	(385,487)
Beginning balance, shares at Dec. 31, 2020	28,516,010	28,516,010
Net loss	$ (71,395)
Ending balance at Jun. 30, 2021	$ 132,128	$ 3	589,007	(456,882)
Ending balance, shares at Jun. 30, 2021	29,186,169	29,186,169
Beginning balance at Mar. 31, 2021	$ 164,339	$ 3	584,666	(420,330)
Beginning balance, shares at Mar. 31, 2021		28,876,510
Issuance of common stock from exercise of stock options	104		104
Issuance of common stock from exercise of stock options, shares		8,000
Vesting of restricted shares, shares		301,659
Stock-based compensation	4,237		4,237
Net loss	(36,552)			(36,552)
Ending balance at Jun. 30, 2021	$ 132,128	$ 3	$ 589,007	$ (456,882)
Ending balance, shares at Jun. 30, 2021	29,186,169	29,186,169