Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Preferred Stock [Member] Series A Convertible Preferred Shares [Member]	Preferred Stock [Member] Series B Convertible Preferred Shares [Member]	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Other Comprehensive Income/(Loss) [Member]	Accumulated Deficit [Member]	Total
Beginning Balance at Dec. 31, 2017	$ 16,060	$ 25,406	$ 68	$ 0	$ 5,340	$ 0	$ (31,355)	$ 15,519
Beginning Balance (in shares) at Dec. 31, 2017	128,738	126,909	6,795,627
Conversion of convertible securities into common shares	$ (16,060)	$ (25,406)	$ 194	0	41,272	0	0	0
Conversion of convertible securities into common shares (in shares)	(128,738)	(126,909)	19,475,788
Exchange of common shares in connection with the Reverse Merger			$ 68	0	85,992	0	0	86,060
Exchange of common shares in connection with the Reverse Merger (in shares)			6,805,608
Issuance of common stock, net of issuance costs			$ 115	0	153,907	0	0	154,022
Issuance of common stock, net of issuance costs (in shares)			11,475,242
Issuance of common stock pursuant to settlement of restricted stock units			$ 3	0	(3)	0	0	0
Issuance of common stock pursuant to settlement of restricted stock units (in shares)			271,718
Issuance of common stock pursuant to exercise of stock options			$ 4	0	144	0	0	148
Issuance of common stock pursuant to exercise of stock options (in shares)			370,753
Stock repurchase			$ 0	(668)	0	0	0	(668)
Stock repurchase (in shares)			0
Unrealized comprehensive gain (loss) on investments			$ 0	0	0	(127)	0	(127)
Share-based compensation			0	0	13,601	0	0	13,601
Net loss			0	0	0	0	(74,518)	(74,518)
Ending Balance at Dec. 31, 2018	$ 0	$ 0	$ 452	(668)	300,253	(127)	(105,873)	194,037
Ending Balance (in shares) at Dec. 31, 2018	0	0	45,194,736
Issuance of common stock, net of issuance costs			$ 96	0	177,664	0	0	177,760
Issuance of common stock, net of issuance costs (in shares)			9,568,000
Issuance of common stock pursuant to exercise of stock options			$ 1	0	30	0	0	31
Issuance of common stock pursuant to exercise of stock options (in shares)			110,325
Stock repurchase			$ 0	(725)		0	0	(726)
Stock repurchase					(1)
Stock repurchase (in shares)			0
Retirement of treasury stock			$ (1)	1,393	(1,392)	0	0	0
Retirement of treasury stock (in shares)			(100,000)
Sale of treasury stock			$ 0	344	0	0	0	344
Sale of treasury stock (in shares)			0
Issuance of treasury stock pursuant to exercise of stock options			$ 0	(397)	0	0	0	(397)
Issuance of treasury stock pursuant to exercise of stock options (in shares)			0
Unrealized comprehensive gain (loss) on investments			$ 0	0	0	147	0	147
Share-based compensation			0	0	13,371	0	0	13,371
Net loss			0	0	0	0	(77,270)	(77,270)
Ending Balance at Dec. 31, 2019			$ 548	(53)	489,925	20	(183,143)	307,297
Ending Balance (in shares) at Dec. 31, 2019			54,773,061
Conversion of convertible securities into common shares			$ 3	0	7,626	0	0	7,629
Conversion of convertible securities into common shares (in shares)			298,562
Issuance of common stock, net of issuance costs			$ 53	0	280,710	0	0	280,763
Issuance of common stock, net of issuance costs (in shares)			5,339,286
Issuance of common stock pursuant to exercise of stock options			$ 6	0	2,552	0	0	2,558
Issuance of common stock pursuant to exercise of stock options (in shares)			586,857
Issuance of common stock pursuant to exercise of warrant (in shares)			1,601
Issuance of warrants					26,562			26,562
Stock repurchase			$ 0	$ 0		0	0	(72)
Stock repurchase					(72)
Stock repurchase (in shares)				(3,000)
Sale of treasury stock			$ 0	$ 667	(76)	0	0	591
Sale of treasury stock (in shares)			0
Issuance of treasury stock pursuant to exercise of stock options			$ 0	(614)	0	0	0	(614)
Issuance of treasury stock pursuant to exercise of stock options (in shares)			0
Unrealized comprehensive gain (loss) on investments			$ 0	0	0	(62)	0	(62)
Share-based compensation			0	0	18,567	0	0	18,567
Net loss			0	0	0	0	(139,700)	(139,700)
Ending Balance at Dec. 31, 2020			$ 610	$ 0	$ 825,794	$ (42)	$ (322,843)	$ 503,519
Ending Balance (in shares) at Dec. 31, 2020			60,996,367