CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (DEFICIT) - USD ($) shares in Thousands, $ in Thousands	Common stock	Additional paid-in capital	Accumulated other comprehensive gain (loss)	Retained earnings/(Accumulated deficit	Total
Beginning balance, shares at Dec. 31, 2014	14,824
Beginning balance, value at Dec. 31, 2014	$ 15	$ 192,112	$ 1,925	$ (79,040)	$ 115,012
Public offering of common stock, net, in shares	1,857
Public offering of common	$ 2	38,646			38,648
Issuance of shares under equity plans, in shares	77
Stock options exercised, net of shares withheld for employee tax, in shares	81
Stock options exercised, net of shares withheld for employee tax, value		452			452
Share based compensation		2,120			2,120
Loss on foreign currency translation adjustment			(1,633)		(1,633)
Other		6			6
Net income				10,793	10,793
Ending balance, shares at Dec. 31, 2015	16,839
Ending balance, value at Dec. 31, 2015	$ 17	233,336	292	(68,247)	165,398
Public offering of common stock, net, in shares	1,126
Public offering of common	$ 1	27,236			27,237
Issuance of shares under equity plans, in shares	276
Stock options exercised, net of shares withheld for employee tax, in shares	159
Stock options exercised, net of shares withheld for employee tax, value		859			859
Share based compensation		3,833			3,833
Loss on foreign currency translation adjustment			(1,177)		(1,177)
Net income				31,234	31,234
Ending balance, shares at Dec. 31, 2016	18,400
Ending balance, value at Dec. 31, 2016	$ 18	265,264	(885)	(37,013)	227,384
Public offering of common stock, net, in shares	459
Public offering of common	$ 1	21,571			21,572
Stock options exercised, net of shares withheld for employee tax, in shares	418
Stock options exercised, net of shares withheld for employee tax, value		(6,630)			(6,630)
Issuance of restricted stock, net of shares withheld for employee tax, in shares	174
Issuance of restricted stock, net of shares withheld for employee tax, value		(2,631)			(2,631)
Share based compensation		7,795			7,795
Cumulative effect of previously unrecognized tax benefits				1,207	1,207
Loss on foreign currency translation adjustment			10,628		10,628
Other		7		(7)
Net income				73,951	73,951
Ending balance, shares at Dec. 31, 2017	19,451
Ending balance, value at Dec. 31, 2017	$ 19	$ 285,376	$ 9,743	$ 38,138	$ 333,276