CONSOLIDATED STATEMENTS OF REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Series A Redeemable Convertible Preferred Stock	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Redeemable preferred stock, beginning balance (in shares) at Dec. 31, 2017		6,864,000
Redeemable preferred stock, beginning balance at Dec. 31, 2017		$ 32,615
Increase (Decrease) in Temporary Equity [Roll Forward]
Redemption of Series A Preferred Stock				$ (21,300)
Redeemable preferred stock, ending balance (in shares) at Mar. 31, 2018		6,864,000
Redeemable preferred stock, ending balance at Mar. 31, 2018	$ 35,471	$ 35,471
Beginning balance (in shares) at Dec. 31, 2017			80,462,574
Beginning balance at Dec. 31, 2017	171,962		$ 80	194,687	$ 274	$ (23,079)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issuance ESPP Plan (in shares)			38,620
Common stock issuance ESPP Plan	267			267
Stock issuance fees and expenses	(97)			(97)
Foreign currency translation adjustments	(45)				(45)
(Loss) gain on effective cash flow hedges	270				270
Issuance of common stock for stock options (in shares)			67,259
Issuance of common stock for stock options	216		$ 1	215
Deemed dividends on preferred stock and amortization of beneficial conversion feature	(2,856)	$ 2,856		(2,856)
ESPP expense	54			54
Stock based compensation expense - options and restricted stock	1,570			1,570
NET INCOME	644					644
Ending balance (in shares) at Mar. 31, 2018			80,568,453
Ending balance at Mar. 31, 2018	171,985		$ 81	193,840	499	(22,435)
Redeemable preferred stock, beginning balance (in shares) at Dec. 31, 2017		6,864,000
Redeemable preferred stock, beginning balance at Dec. 31, 2017		$ 32,615
Redeemable preferred stock, ending balance (in shares) at Sep. 30, 2018		0
Redeemable preferred stock, ending balance at Sep. 30, 2018		$ 0
Beginning balance (in shares) at Dec. 31, 2017			80,462,574
Beginning balance at Dec. 31, 2017	171,962		$ 80	194,687	274	(23,079)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
(Loss) gain on effective cash flow hedges	298
NET INCOME	2,287
Gain on redemption of preferred stock	9,075
Ending balance (in shares) at Sep. 30, 2018			92,980,783
Ending balance at Sep. 30, 2018	303,559		$ 93	322,592	536	(19,662)
Redeemable preferred stock, beginning balance (in shares) at Mar. 31, 2018		6,864,000
Redeemable preferred stock, beginning balance at Mar. 31, 2018	35,471	$ 35,471
Increase (Decrease) in Temporary Equity [Roll Forward]
Redemption of Series A Preferred Stock (in shares)		(6,864,000)
Redemption of Series A Preferred Stock	(21,348)	$ (37,823)		(21,348)
Redeemable preferred stock, ending balance (in shares) at Jun. 30, 2018		0
Redeemable preferred stock, ending balance at Jun. 30, 2018		$ 0
Beginning balance (in shares) at Mar. 31, 2018			80,568,453
Beginning balance at Mar. 31, 2018	171,985		$ 81	193,840	499	(22,435)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issuance ESPP Plan (in shares)			31,686
Common stock issuance ESPP Plan	231			231
Stock issuance fees and expenses	(46)			(46)
Foreign currency translation adjustments	24				24
(Loss) gain on effective cash flow hedges	(266)				(266)
Issuance of common stock for stock options (in shares)			897,942
Issuance of common stock for stock options	4,918			4,918
Deemed dividends on preferred stock and amortization of beneficial conversion feature	(2,352)	2,352		(2,352)
ESPP expense	56			56
Stock based compensation expense - options and restricted stock	2,277			2,277
NET INCOME	(380)					(380)
Gain on redemption of preferred stock	9,075	$ 0		9,075
Ending balance (in shares) at Jun. 30, 2018			81,498,081
Ending balance at Jun. 30, 2018	164,209		$ 81	185,556	257	(21,685)
Redeemable preferred stock, ending balance (in shares) at Sep. 30, 2018		0
Redeemable preferred stock, ending balance at Sep. 30, 2018		$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issuance ESPP Plan (in shares)			16,689
Common stock issuance ESPP Plan	267			267
Stock issuance fees and expenses	(163)			(163)
Foreign currency translation adjustments	(13)				(13)
(Loss) gain on effective cash flow hedges	292				292
Issuance of restricted stock, net of forfeitures (in shares)			62,182
Issuance of restricted stock, net of forfeitures	(297)			(297)
Issuance of common stock - Public Offering (in shares)			11,270,000
Issuance of common stock - Public Offering	135,071		$ 11	135,060
Issuance of common stock for stock options (in shares)			133,831
Issuance of common stock for stock options	979		$ 1	978
ESPP expense	56			56
Stock based compensation expense - options and restricted stock	1,135			1,135
NET INCOME	2,023					2,023
Gain on redemption of preferred stock	0
Ending balance (in shares) at Sep. 30, 2018			92,980,783
Ending balance at Sep. 30, 2018	303,559		$ 93	322,592	536	(19,662)
Redeemable preferred stock, beginning balance (in shares) at Dec. 31, 2018		0
Redeemable preferred stock, beginning balance at Dec. 31, 2018		$ 0
Redeemable preferred stock, ending balance (in shares) at Mar. 31, 2019		0
Redeemable preferred stock, ending balance at Mar. 31, 2019		$ 0
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)
(Loss) gain on effective cash flow hedges	(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	(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)
Redeemable preferred stock, beginning balance (in shares) at Dec. 31, 2018		0
Redeemable preferred stock, beginning balance at Dec. 31, 2018		$ 0
Redeemable preferred stock, ending balance (in shares) at Sep. 30, 2019		0
Redeemable preferred stock, ending balance at Sep. 30, 2019		$ 0
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]
(Loss) gain on effective cash flow hedges	$ (1,801)
Issuance of common stock for stock options (in shares)	1,439,869
NET INCOME	$ 1,710
Gain on redemption of preferred stock	0
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)
Redeemable preferred stock, beginning balance (in shares) at Mar. 31, 2019		0
Redeemable preferred stock, beginning balance at Mar. 31, 2019		$ 0
Redeemable preferred stock, ending balance (in shares) at Jun. 30, 2019		0
Redeemable preferred stock, ending balance at Jun. 30, 2019		$ 0
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)
(Loss) gain on effective cash flow hedges	(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	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)
Redeemable preferred stock, ending balance (in shares) at Sep. 30, 2019		0
Redeemable preferred stock, ending balance at Sep. 30, 2019		$ 0
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
(Loss) gain on effective cash flow hedges	(217)				(217)
Issuance of restricted stock, net of forfeitures (in shares)			(6,070)
Issuance of restricted stock, net of forfeitures	(688)			(688)
Issuance of common stock for stock options (in shares)			289,081
Issuance of common stock for stock options	2,173			2,173
ESPP expense	144			144
Stock based compensation expense - options and restricted stock	3,131			3,131
NET INCOME	2,143					2,143
Gain on redemption of preferred stock	0
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)