CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
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)		36,032
Common stock issuance ESPP Plan	419		419
Stock issuance fees and expenses	(66)		(66)
Gain (loss) on effective cash flow hedge	(557)			(557)
Issuance of restricted stock, net of forfeitures (in shares)		182,502
Issuance of common stock for stock options (in shares)		619,536
Issuance of common stock for stock options	3,894	$ 1	3,893
ESPP expense	119		119
Stock-based compensation expense - options and restricted stock	2,020		2,020
NET INCOME (LOSS)	(2,424)				(2,424)
Ending balance (in shares) at Mar. 31, 2019		95,303,510
Ending balance at Mar. 31, 2019	323,848	$ 95	346,676	(1,136)	(21,787)
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]
Unrealized loss on securities, net	0
Cash flow hedge termination reclassified to earnings	0
NET INCOME (LOSS)	1,710
Ending balance (in shares) at Sep. 30, 2019		104,145,895
Ending balance at Sep. 30, 2019	497,007	$ 104	516,936	(2,380)	(17,653)
Beginning balance (in shares) at Mar. 31, 2019		95,303,510
Beginning balance at Mar. 31, 2019	323,848	$ 95	346,676	(1,136)	(21,787)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issuance ESPP Plan (in shares)		37,255
Common stock issuance ESPP Plan	653		653
Stock issuance fees and expenses	(211)		(211)
Gain (loss) on effective cash flow hedge	(1,027)			(1,027)
Issuance of restricted stock, net of forfeitures (in shares)		(633)
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 (in shares)		8,050,000
Issuance of common stock - Public Offering	160,774	$ 8	160,766
Issuance of common stock for stock options (in shares)		543,604
Issuance of common stock for stock options	3,370	$ 1	3,369
ESPP expense	162		162
Stock-based compensation expense - options and restricted stock	2,151		2,151
NET INCOME (LOSS)	1,991				1,991
Ending balance (in shares) at Jun. 30, 2019		103,834,212
Ending balance at Jun. 30, 2019	489,734	$ 104	511,589	(2,163)	(19,796)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issuance ESPP Plan (in shares)		28,672
Common stock issuance ESPP Plan	564		564
Stock issuance fees and expenses	23		23
Unrealized loss on securities, net	0
Gain (loss) on effective cash flow hedge	(217)			(217)
Cash flow hedge termination reclassified to earnings	0
Issuance of restricted stock, net of forfeitures (in shares)		(6,070)
Issuance of restricted stock, net of forfeitures	$ (688)
Issuance of common stock for stock options (in shares)	289,081
Issuance of common stock for stock options	$ 2,173
ESPP expense	144		144
Stock-based compensation expense - options and restricted stock	3,131		3,131
NET INCOME (LOSS)	2,143				2,143
Ending balance (in shares) at Sep. 30, 2019		104,145,895
Ending balance at Sep. 30, 2019	497,007	$ 104	516,936	(2,380)	(17,653)
Beginning balance (in shares) at Dec. 31, 2019		104,781,236
Beginning 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)		34,330
Common stock issuance ESPP Plan	796		796
Stock issuance fees and expenses	(15)		(15)
Gain (loss) on effective cash flow hedge	(1,038)			(1,038)
Issuance of restricted stock, net of forfeitures (in shares)		76,618
Issuance of restricted stock, net of forfeitures	(212)		(212)
Issuance of common stock for stock options (in shares)		503,873
Issuance of common stock for stock options	2,897		2,897
ESPP expense	194		194
Stock-based compensation expense - options and restricted stock	1,991		1,991
NET INCOME (LOSS)	(6,978)				(6,978)
Ending balance (in shares) at Mar. 31, 2020		105,396,057
Ending balance at Mar. 31, 2020	505,043	$ 105	525,929	(2,656)	(18,335)
Beginning balance (in shares) at Dec. 31, 2019		104,781,236
Beginning balance at Dec. 31, 2019	507,408	$ 105	520,278	(1,618)	(11,357)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Unrealized loss on securities, net	(21)
Cash flow hedge termination reclassified to earnings	$ 2,661
Issuance of common stock for stock options (in shares)	1,276,144
NET INCOME (LOSS)	$ (11,245)
Ending balance (in shares) at Sep. 30, 2020		111,010,418
Ending balance at Sep. 30, 2020	666,363	$ 111	688,832	22	(22,602)
Beginning balance (in shares) at Mar. 31, 2020		105,396,057
Beginning balance at Mar. 31, 2020	505,043	$ 105	525,929	(2,656)	(18,335)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issuance ESPP Plan (in shares)		41,058
Common stock issuance ESPP Plan	928		928
Stock issuance fees and expenses	(209)		(209)
Gain (loss) on effective cash flow hedge	38			38
Cash flow hedge termination reclassified to earnings	2,661			2,661
Issuance of restricted stock, net of forfeitures (in shares)		24,786
Issuance of restricted stock, net of forfeitures	(824)		(824)
Issuance of common stock - Public Offering (in shares)		4,751,500
Issuance of common stock - Public Offering	127,293	$ 5	127,288
Issuance of common stock for stock options (in shares)		183,443
Issuance of common stock for stock options	2,014		2,014
ESPP expense	211		211
Stock-based compensation expense - options and restricted stock	2,424		2,424
Equity component of convertible note issuance	30,912		30,912
Tax liability related to convertible note issuance	(9,330)		(9,330)
Convertible note debt issuance costs	(108)		(108)
NET INCOME (LOSS)	(6,824)				(6,824)
Ending balance (in shares) at Jun. 30, 2020		110,396,844
Ending balance at Jun. 30, 2020	654,229	$ 110	679,235	43	(25,159)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issuance ESPP Plan (in shares)		29,853
Common stock issuance ESPP Plan	808		808
Stock issuance fees and expenses	(29)		(29)
Unrealized loss on securities, net	(21)			(21)
Cash flow hedge termination reclassified to earnings	0
Issuance of restricted stock, net of forfeitures (in shares)		(1,124)
Issuance of restricted stock, net of forfeitures	(237)		(237)
Issuance of common stock for stock options (in shares)		584,845
Issuance of common stock for stock options	4,846	$ 1	4,845
ESPP expense	222		222
Stock-based compensation expense - options and restricted stock	2,494		2,494
Adjustment to tax liability related to convertible note issuance	1,524		1,524
Convertible note debt issuance costs	(30)		(30)
NET INCOME (LOSS)	2,557				2,557
Ending balance (in shares) at Sep. 30, 2020		111,010,418
Ending balance at Sep. 30, 2020	$ 666,363	$ 111	$ 688,832	$ 22	$ (22,602)