Consolidated Statements of Shareholders' Equity (Deficit) (USD $) In Thousands, except Share data	Common Stock [Member] Redeemable Convertible Preferred Stock [Member]	Common Stock [Member] Redeemable Common Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member] Redeemable Convertible Preferred Stock [Member]	Additional Paid-in Capital [Member] Redeemable Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Redeemable Convertible Preferred Stock [Member]	Redeemable Common Stock [Member]	Total
Balance at Dec. 31, 2010			$ 8			$ 5,896	$ (41,537)	$ (458)			$ (36,091)
Balance (in Shares) at Dec. 31, 2010			8,013,250
Common shares issued on exercise of options						706					706
Common shares issued on exercise of options (in Shares)			166,838
Common shares issued on exercise of warrants			2			497					499
Common shares issued on exercise of warrants (in Shares)			1,526,182
Preferred stock dividends							(4,179)				(4,179)
Stock-based compensation expense						1,130					1,130
Net income							17,972				17,972
Foreign currency translation adjustment								(280)			(280)
Comprehensive income											17,692
Balance at Dec. 31, 2011			10			8,229	(27,744)	(738)			(20,243)
Balance (in Shares) at Dec. 31, 2011			9,706,270
Common shares issued upon initial public offering			5			71,525					71,530
Common shares issued upon initial public offering (in Shares)			4,945,000
Common shares issued upon follow-on offering						2,451					2,451
Common shares issued upon follow-on offering (in Shares)			100,000
Common shares issued upon conversion of redeemable stock	6	3		66,069	816				66,075	819
Common shares issued upon conversion of redeemable stock (in Shares)	5,991,790	3,189,648
Common shares issued on exercise of options			1			2,974					2,975
Common shares issued on exercise of options (in Shares)			870,932
Excess tax benefit from stock option exercises						6,218					6,218
Preferred stock dividends						(14,289)	14,289
Stock-based compensation expense						3,039					3,039
Net income							24,025				24,025
Foreign currency translation adjustment								(190)			(190)
Comprehensive income											23,835
Balance at Dec. 31, 2012			25			147,032	10,570	(928)			156,699
Balance (in Shares) at Dec. 31, 2012			24,803,640								24,803,640
Common shares issued on exercise of options			1			6,495					6,496
Common shares issued on exercise of options (in Shares)			742,467
Excess tax benefit from stock option exercises						9,873					9,873
Stock-based compensation expense						3,461					3,461
Net income							35,277				35,277
Foreign currency translation adjustment								(163)			(163)
Comprehensive income											35,114
Balance at Dec. 31, 2013			$ 26			$ 166,861	$ 45,847	$ (1,091)			$ 211,643
Balance (in Shares) at Dec. 31, 2013			25,546,107								25,546,107