CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (DEFICIT) (Unaudited) - USD ($) $ in Thousands	Total	Series D Preferred Stock	Convertible Preferred Stock	Transition Adjustment	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income	Accumulated Deficit	Accumulated Deficit Transition Adjustment
Beginning balance at Dec. 31, 2019	$ (149,511)			$ 111	$ 2	$ 2,689	$ 19	$ (152,221)	$ 111
Beginning balance, Shares at Dec. 31, 2019			32,934,785
Beginning balance at Dec. 31, 2019			$ 222,173
Beginning balance, Shares at Dec. 31, 2019					13,196,419
Accounting Standards Update Extensible List	ASC 842
Issuance of common stock under employee stock compensation plans	$ 183					183
Issuance of common stock under employee stock compensation plans, Shares					174,359
Stock-based compensation expense	1,509					1,509
Unrealized gain (loss) on available-for-sale investments	111						111
Net loss	(28,784)							(28,784)
Ending balance at Mar. 31, 2020	(176,381)				$ 2	4,381	130	(180,894)
Ending balance, Shares at Mar. 31, 2020			32,934,785
Ending balance at Mar. 31, 2020			$ 222,173
Ending balance, Shares at Mar. 31, 2020					13,370,778
Beginning balance at Dec. 31, 2019	(149,511)			$ 111	$ 2	2,689	19	(152,221)	$ 111
Beginning balance, Shares at Dec. 31, 2019			32,934,785
Beginning balance at Dec. 31, 2019			$ 222,173
Beginning balance, Shares at Dec. 31, 2019					13,196,419
Unrealized gain (loss) on available-for-sale investments	1
Net loss	(59,212)
Ending balance at Jun. 30, 2020	(205,303)				$ 2	5,997	20	(211,322)
Ending balance, Shares at Jun. 30, 2020			42,953,085
Ending balance at Jun. 30, 2020			$ 326,313
Ending balance, Shares at Jun. 30, 2020					13,370,778
Beginning balance at Mar. 31, 2020	(176,381)				$ 2	4,381	130	(180,894)
Beginning balance, Shares at Mar. 31, 2020			32,934,785
Beginning balance at Mar. 31, 2020			$ 222,173
Beginning balance, Shares at Mar. 31, 2020					13,370,778
Issuance of preferred stock for cash net of issuance costs, Shares		10,018,300
Issuance of preferred stock for cash net of issuance costs		$ 104,140
Stock-based compensation expense	1,616					1,616
Unrealized gain (loss) on available-for-sale investments	(110)						(110)
Net loss	(30,428)							(30,428)
Ending balance at Jun. 30, 2020	(205,303)				$ 2	5,997	20	(211,322)
Ending balance, Shares at Jun. 30, 2020			42,953,085
Ending balance at Jun. 30, 2020			$ 326,313
Ending balance, Shares at Jun. 30, 2020					13,370,778
Beginning balance at Dec. 31, 2020	261,968				$ 6	543,842	5	(281,885)
Beginning balance, Shares at Dec. 31, 2020					61,860,897
Issuance of common stock under employee stock compensation plans	360					360
Issuance of common stock under employee stock compensation plans, Shares					265,839
Stock-based compensation expense	3,462					3,462
Unrealized gain (loss) on available-for-sale investments	10						10
Net loss	(38,314)							(38,314)
Ending balance at Mar. 31, 2021	227,486				$ 6	547,664	15	(320,199)
Ending balance, Shares at Mar. 31, 2021					62,126,736
Beginning balance at Dec. 31, 2020	261,968				$ 6	543,842	5	(281,885)
Beginning balance, Shares at Dec. 31, 2020					61,860,897
Unrealized gain (loss) on available-for-sale investments	(4)
Net loss	(84,019)
Ending balance at Jun. 30, 2021	186,576				$ 6	552,473	1	(365,904)
Ending balance, Shares at Jun. 30, 2021					62,166,167
Beginning balance at Mar. 31, 2021	227,486				$ 6	547,664	15	(320,199)
Beginning balance, Shares at Mar. 31, 2021					62,126,736
Issuance of common stock under employee stock compensation plans	67					67
Issuance of common stock under employee stock compensation plans, Shares					39,431
Stock-based compensation expense	4,742					4,742
Unrealized gain (loss) on available-for-sale investments	(14)						(14)
Net loss	(45,705)							(45,705)
Ending balance at Jun. 30, 2021	$ 186,576				$ 6	$ 552,473	$ 1	$ (365,904)
Ending balance, Shares at Jun. 30, 2021					62,166,167