CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Cumulative-effect adjustment from change in accounting principle	Common Stock	Additional Paid-In Capital	Additional Paid-In Capital Cumulative-effect adjustment from change in accounting principle	Accumulated Other Comprehensive (Loss) Income	(Accumulated Deficit) Retained Earnings	(Accumulated Deficit) Retained Earnings Cumulative-effect adjustment from change in accounting principle
Beginning balance (in shares) at Dec. 31, 2020			112,075,474
Beginning balance at Dec. 31, 2020	$ 694,294	$ (22,575)	$ 112	$ 701,357	$ (23,271)	$ 10	$ (7,185)	$ 696
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issuance ESPP Plan (in shares)			23,917
Common stock issuance ESPP Plan	1,024			1,024
Premiums paid for capped call confirmations	(29,291)			(29,291)
Issuance of restricted stock, net of forfeitures (in shares)			83,220
Issuance of restricted stock, net of forfeitures	(614)			(614)
Issuance of common stock for stock options (in shares)			260,167
Issuance of common stock for stock options	2,239			2,239
Issuance of common stock - public offering, net of underwriting discounts (in shares)			4,693,876
Issuance of common stock - public offering, net of underwriting discounts	218,500		$ 5	218,495
Stock issuance fees and expenses	(242)			(242)
ESPP expense	241			241
Stock-based compensation expense - options and restricted stock	2,412			2,412
Net unrealized loss on marketable securities, net of tax	(160)					(160)
Net loss	(22,114)						(22,114)
Ending balance (in shares) at Mar. 31, 2021			117,136,654
Ending balance at Mar. 31, 2021	843,714		$ 117	872,350		(150)	(28,603)
Beginning balance (in shares) at Dec. 31, 2021			124,107,500
Beginning balance at Dec. 31, 2021	1,108,277		$ 124	1,123,628		(638)	(14,837)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issuance ESPP Plan (in shares)			47,853
Common stock issuance ESPP Plan	971			971
Issuance of restricted stock, net of forfeitures (in shares)			100,253
Issuance of restricted stock, net of forfeitures	$ (1,049)			(1,049)
Issuance of common stock for stock options (in shares)	471,609		466,609
Issuance of common stock for stock options	$ 6,480		$ 1	6,479
ESPP expense	249			249
Stock-based compensation expense - options and restricted stock	11,855			11,855
Net unrealized loss on marketable securities, net of tax	(2,371)					(2,371)
Net loss	(49,408)						(49,408)
Ending balance (in shares) at Mar. 31, 2022			124,722,215
Ending balance at Mar. 31, 2022	$ 1,075,004		$ 125	$ 1,142,133		$ (3,009)	$ (64,245)