Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Stock	Additional Paid-in Capital	Additional Paid-in Capital Cumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive (Loss) Income	Accumulated Deficit	Accumulated Deficit Cumulative Effect, Period of Adoption, Adjustment
Beginning balance (in shares) at Dec. 31, 2018			94,465,440
Beginning balance at Dec. 31, 2018	$ 320,443		$ 94	$ 340,291		$ (579)	$ (19,363)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issuance ESPP plan (in shares)	141,908		141,908
Common stock issuance ESPP Plan	$ 2,332			2,332
Stock issuance fees and expenses	(263)			(263)
Loss on effective cash flow hedge	(1,039)					(1,039)
Issuance of restricted stock, net of forfeitures (in shares)			168,501
Issuance of restricted stock, net of forfeitures	(837)			(837)
Net unrealized loss on marketable securities, net of tax	0
Working capital adjustment related to acquisition (in shares)			(99,524)
Working capital adjustment related to acquisition	(1,977)			(1,977)
Issuance of common stock - public offering, net of underwriting discounts (in shares)			8,050,000
Issuance of common stock - public offering, net of underwriting discounts	$ 160,774		$ 8	160,766
Issuance of common stock for stock options (in shares)	2,309,451		2,054,911
Issuance of common stock for stock options	$ 9,974		$ 3	9,971
ESPP expense	609			609
Stock-based compensation expense - options and restricted stock	9,386			9,386
Net income (loss)	8,006						8,006
Ending balance (in shares) at Dec. 31, 2019			104,781,236
Ending balance at Dec. 31, 2019	$ 507,408		$ 105	520,278		(1,618)	(11,357)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issuance ESPP plan (in shares)	138,309		138,309
Common stock issuance ESPP Plan	$ 3,579			3,579
Stock issuance fees and expenses	(268)			(268)
Loss on effective cash flow hedge	(1,000)					(1,000)
Issuance of restricted stock, net of forfeitures (in shares)			97,478
Issuance of restricted stock, net of forfeitures	(1,276)			(1,276)
Cash flow hedge termination reclassified to earnings	2,661					2,661
Net unrealized loss on marketable securities, net of tax	(33)					(33)
Working capital adjustment related to acquisition	0
Issuance of common stock - public offering, net of underwriting discounts (in shares)			4,751,500
Issuance of common stock - public offering, net of underwriting discounts	$ 127,293		$ 5	127,288
Issuance of common stock for stock options (in shares)	2,310,934		2,306,951
Issuance of common stock for stock options	$ 18,275		$ 2	18,273
ESPP expense	875			875
Stock-based compensation expense - options and restricted stock	9,337			9,337
Equity component of Convertible Senior Notes due 2025	30,912			30,912
Tax liability related to Convertible Senior Notes due 2025	(7,504)			(7,504)
Convertible note debt issuance costs	(137)			(137)
Net income (loss)	4,172						4,172
Ending balance (in shares) at Dec. 31, 2020			112,075,474
Ending balance at Dec. 31, 2020	$ 694,294	$ (22,576)	$ 112	701,357	$ (23,271)	10	(7,185)	$ 695
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issuance ESPP plan (in shares)	112,094		112,094
Common stock issuance ESPP Plan	$ 4,360			4,360
Premiums paid for capped call confirmations	(29,291)			(29,291)
Stock issuance fees and expenses	(372)			(372)
Issuance of restricted stock, net of forfeitures (in shares)			811,335
Issuance of restricted stock, net of forfeitures	(2,817)		$ 1	(2,818)
Net unrealized loss on marketable securities, net of tax	(648)					(648)
Working capital adjustment related to acquisition	0
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
Issuance of common stock for stock options (in shares)	1,372,564		1,372,564
Issuance of common stock for stock options	$ 13,678		$ 1	13,677
Issuance of common stock - private placement, net of private placement fees (in shares)			4,444,445
Issuance of common stock - private placement, net of private placement fees	189,863		$ 4	189,859
ESPP expense	1,052			1,052
Issuance of common stock for acquisition (in shares)			597,712
Issuance of common stock for acquisition	29,175		$ 1	29,174
Stock-based compensation expense - options and restricted stock	21,406			21,406
Net income (loss)	(8,347)						(8,347)
Ending balance (in shares) at Dec. 31, 2021			124,107,500
Ending balance at Dec. 31, 2021	$ 1,108,277		$ 124	$ 1,123,628		$ (638)	$ (14,837)