CONSOLIDATED STATEMENTS OF STOCKHOLDERS' DEFICIT - USD ($) $ in Thousands	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit	Total
Beginning Balance at Dec. 31, 2020	$ 104	$ 2,498,179	$ (44,304)	$ (2,612,727)	$ (158,748)
Beginning Balance (in shares) at Dec. 31, 2020	103,699,109
Exercise of stock options		27			27
Exercise of stock options (in shares)	5,609
Issuance of common stock from vesting of restricted stock units	$ 1	(1)
Issuance of common stock from vesting of restricted stock units (in shares)	853,239
Share-based compensation expense		4,039			4,039
Foreign currency translation adjustments			(80)		(80)
Net loss				(66,277)	(66,277)
Ending Balance at Mar. 31, 2021	$ 105	2,502,244	(44,384)	(2,679,004)	(221,039)
Ending Balance (in shares) at Mar. 31, 2021	104,557,957
Beginning Balance at Dec. 31, 2020	$ 104	2,498,179	(44,304)	(2,612,727)	(158,748)
Beginning Balance (in shares) at Dec. 31, 2020	103,699,109
Foreign currency translation adjustments					(66)
Net loss					(132,725)
Ending Balance at Jun. 30, 2021	$ 118	2,582,721	(44,370)	(2,745,452)	(206,983)
Ending Balance (in shares) at Jun. 30, 2021	118,403,984
Beginning Balance at Mar. 31, 2021	$ 105	2,502,244	(44,384)	(2,679,004)	(221,039)
Beginning Balance (in shares) at Mar. 31, 2021	104,557,957
Exercise of stock options		9			9
Exercise of stock options (in shares)	1,478
Issuance of common stock from vesting of restricted stock units (in shares)	193,936
Share-based compensation expense		7,362			7,362
Foreign currency translation adjustments			14		14
Issuance of common stock, net of issuance costs	$ 13	72,459			72,472
Issuance of common stock, net of issuance costs (in shares)	13,492,231
Issuance of common stock under employee stock purchase plan		647			647
Issuance of common stock under employee stock purchase plan (in shares)	158,382
Net loss				(66,448)	(66,448)
Ending Balance at Jun. 30, 2021	$ 118	2,582,721	(44,370)	(2,745,452)	(206,983)
Ending Balance (in shares) at Jun. 30, 2021	118,403,984
Beginning Balance at Dec. 31, 2021	$ 129	2,641,712	(43,430)	(2,877,251)	$ (278,840)
Beginning Balance (in shares) at Dec. 31, 2021	129,109,543				129,109,543
Issuance of common stock from vesting of restricted stock units	$ 1	(1)
Issuance of common stock from vesting of restricted stock units (in shares)	889,273
Share-based compensation expense		6,632			$ 6,632
Foreign currency translation adjustments			435		435
Issuance of common stock, net of issuance costs	$ 14	28,622			28,636
Issuance of common stock, net of issuance costs (in shares)	13,870,410
Net loss				(60,169)	(60,169)
Ending Balance at Mar. 31, 2022	$ 144	2,676,965	(42,995)	(2,937,420)	(303,306)
Ending Balance (in shares) at Mar. 31, 2022	143,869,226
Beginning Balance at Dec. 31, 2021	$ 129	2,641,712	(43,430)	(2,877,251)	$ (278,840)
Beginning Balance (in shares) at Dec. 31, 2021	129,109,543				129,109,543
Foreign currency translation adjustments					$ 1,593
Net loss					(131,500)
Ending Balance at Jun. 30, 2022	$ 144	2,682,750	(41,837)	(3,008,752)	$ (367,695)
Ending Balance (in shares) at Jun. 30, 2022	144,472,733				144,472,733
Beginning Balance at Mar. 31, 2022	$ 144	2,676,965	(42,995)	(2,937,420)	$ (303,306)
Beginning Balance (in shares) at Mar. 31, 2022	143,869,226
Issuance of common stock from vesting of restricted stock units (in shares)	347,079
Share-based compensation expense		5,402			5,402
Foreign currency translation adjustments			1,158		1,158
Issuance of common stock under employee stock purchase plan		392			392
Issuance of common stock under employee stock purchase plan (in shares)	256,428
Other financing costs		(9)			(9)
Net loss				(71,332)	(71,332)
Ending Balance at Jun. 30, 2022	$ 144	$ 2,682,750	$ (41,837)	$ (3,008,752)	$ (367,695)
Ending Balance (in shares) at Jun. 30, 2022	144,472,733				144,472,733