CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (USD $) In Thousands, except Share data, unless otherwise specified	Common Stock [Member]	Warrants to acquire Common Stock [Member]	Retained Earnings (Accumulated Deficit) [Member]	Other Comprehensive Loss [Member]	Total
BALANCES at Dec. 31, 2010	$ 182,466	$ 19,673	$ (115,387)	$ 0	$ 86,752
BALANCES (in shares) at Dec. 31, 2010	93,975,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Consolidated net income	0	0	43,013	0	43,013
Exercise of stock warrants	3,454	(1,727)	0	0	1,727
Exercise of stock warrants (in shares)	365,000
Exercise of stock options	867	0	0	0	867
Exercise of stock options (in shares)	454,000
Employee stock purchase plan issuances	220	0	0	0	220
Employee stock purchase plan issuances (in shares)	129,000
Restricted stock awards	17	0	0	0	17
Restricted stock awards (in shares)	15,000
Equity portion of convertible notes offering	20,470	0	0	0	20,470
Stock-based compensation expense	5,142	0	0	0	5,142
BALANCES at Dec. 31, 2011	212,636	17,946	(72,374)	0	158,202
BALANCES (in shares) at Dec. 31, 2011	94,938,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Consolidated net income	0	0	35,378	0	35,378
Exercise of stock options	1,511	0	0	0	1,511
Exercise of stock options (in shares)	806,000
Employee stock purchase plan issuances	368	0	0	0	368
Employee stock purchase plan issuances (in shares)	71,000
Restricted stock awards	351	0	0	0	351
Restricted stock awards (in shares)	29,000
Stock-based compensation expense	6,681	0	0	0	6,681
Foreign currency translation loss	0	0	0	(5,904)	(5,904)
Excess tax benefit - stock compensation	4,488	0	0	0	4,488
BALANCES at Dec. 31, 2012	226,035	17,946	(36,996)	(5,904)	201,081
BALANCES (in shares) at Dec. 31, 2012	95,844,000				95,844,012
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Consolidated net income	0	0	52,362	0	52,362
Exercise of stock options	2,634	0	0	0	2,634
Exercise of stock options (in shares)	630,000
Employee stock purchase plan issuances	588	0	0	0	588
Employee stock purchase plan issuances (in shares)	61,000
Restricted stock awards	579	0	0	0	579
Restricted stock awards (in shares)	34,000
Stock-based compensation expense	6,471	0	0	0	6,471
Foreign currency translation loss	0	0	0	(6,463)	(6,463)
Excess tax benefit - stock compensation	2,928	0	0	0	2,928
BALANCES at Dec. 31, 2013	$ 239,235	$ 17,946	$ 15,366	$ (12,367)	$ 260,180
BALANCES (in shares) at Dec. 31, 2013	96,569,000				96,569,186