Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common stock	Additional paid-in capital	Accumulated deficit	Accumulated other comprehensive income (loss)
Beginning balance (in shares) at Dec. 31, 2019		61,635,477
Beginning balance at Dec. 31, 2019	$ 352,485	$ 7	$ 686,390	$ (334,170)	$ 258
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Vesting of restricted stock (in shares)		404,637
Exercise of stock option (in shares)		4,309
Exercise of stock options	15		15
Stock-based compensation	8,244		8,244
Issuance of common stock pursuant to Employee Stock Purchase Plan (in shares)		49,889
Issuance of common stock pursuant to Employee Stock Purchase Plan	556		556
Net loss	(54,074)			(54,074)
Other comprehensive income (loss)	(763)				(763)
Ending balance (in shares) at Mar. 31, 2020		62,094,312
Ending balance at Mar. 31, 2020	306,463	$ 7	695,205	(388,244)	(505)
Beginning balance (in shares) at Dec. 31, 2019		61,635,477
Beginning balance at Dec. 31, 2019	352,485	$ 7	686,390	(334,170)	258
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(120,944)
Other comprehensive income (loss)	309
Ending balance (in shares) at Jun. 30, 2020		71,972,610
Ending balance at Jun. 30, 2020	420,324	$ 8	874,863	(455,114)	567
Beginning balance (in shares) at Mar. 31, 2020		62,094,312
Beginning balance at Mar. 31, 2020	306,463	$ 7	695,205	(388,244)	(505)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Vesting of restricted stock (in shares)		404,637
Issuance of common stock in connection with public offering, net of underwriting discounts, commissions, and offering costs (in shares)		9,433,963
Issuance of common stock in connection with public offering, net of underwriting discounts, commissions, and offering costs	117,094	$ 1	117,093
Equity component of convertible note issuance	53,635		53,635
Debt issuance costs attributable to convertible feature	(109)		(109)
Exercise of stock option (in shares)		39,698
Exercise of stock options	139		139
Stock-based compensation	8,900		8,900
Net loss	(66,870)			(66,870)
Other comprehensive income (loss)	1,072				1,072
Ending balance (in shares) at Jun. 30, 2020		71,972,610
Ending balance at Jun. 30, 2020	420,324	$ 8	874,863	(455,114)	567
Beginning balance (in shares) at Dec. 31, 2020		73,874,904
Beginning balance at Dec. 31, 2020	320,684	$ 8	897,607	(577,530)	599
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Vesting of restricted stock (in shares)		238,962
Exercise of stock option (in shares)		5,721
Exercise of stock options	15		15
Stock-based compensation	8,708		8,708
Issuance of common stock pursuant to Employee Stock Purchase Plan (in shares)		95,004
Issuance of common stock pursuant to Employee Stock Purchase Plan	759		759
Issuance of common stock for restricted stock units vested (in shares)		278,559
Net loss	(57,641)			(57,641)
Other comprehensive income (loss)	(441)				(441)
Ending balance (in shares) at Mar. 31, 2021		74,493,150
Ending balance at Mar. 31, 2021	272,084	$ 8	907,089	(635,171)	158
Beginning balance (in shares) at Dec. 31, 2020		73,874,904
Beginning balance at Dec. 31, 2020	$ 320,684	$ 8	897,607	(577,530)	599
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock option (in shares)	109,643
Net loss	$ (117,473)
Other comprehensive income (loss)	(325)
Ending balance (in shares) at Jun. 30, 2021		74,834,952
Ending balance at Jun. 30, 2021	220,693	$ 8	915,414	(695,003)	274
Beginning balance (in shares) at Mar. 31, 2021		74,493,150
Beginning balance at Mar. 31, 2021	272,084	$ 8	907,089	(635,171)	158
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Vesting of restricted stock (in shares)		231,710
Vesting of restricted stock	0
Exercise of stock option (in shares)		103,922
Exercise of stock options	271		271
Stock-based compensation	8,054		8,054
Issuance of common stock for restricted stock units vested (in shares)		6,170
Net loss	(59,832)			(59,832)
Other comprehensive income (loss)	116				116
Ending balance (in shares) at Jun. 30, 2021		74,834,952
Ending balance at Jun. 30, 2021	$ 220,693	$ 8	$ 915,414	$ (695,003)	$ 274