Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Income Statement [Abstract]
Revenue	$ 371,065		$ 312,828		$ 258,785
Cost of revenue	223,538		181,209		152,965
Gross margin	147,527		131,619		105,820
Expenses:
Selling, general and administrative	78,197		66,415		50,612
Depreciation and amortization	7,273		4,410		3,983
Research and development	3,752		3,182		2,337
Gain on disposal of long-lived assets	(421)		(1,009)		0
Total expenses	88,801		72,998		56,932
Income from operations	58,726		58,621		48,888
Other income (expense):
Loss on extinguishment of debt	0		(7,257)		(3,225)
Change in fair value of warrant liability	0		2,649		9,571
Interest expense	(2,092)		(8,103)		(15,960)
Other income (expense), net	316		(452)		(4)
Total other income (expense)	(1,776)		(13,163)		(9,618)
Income before income taxes	56,950		45,458		39,270
Income tax (expense) benefit	(20,772)		4,333		(7,862)
Net income	36,178		49,791		31,408
Accrued dividends and accretion of discount on preferred stock	0		0		(4,868)
Net income attributable to common stockholders	$ 36,178		$ 49,791		$ 26,540
Earnings per common share:
Basic earnings per common share	$ 0.70	[1]	$ 1.03	[1]	$ 0.60
Diluted earnings per common share	$ 0.67	[1]	$ 0.97	[1]	$ 0.56
Weighted average common shares:
Weighted average common shares used in computing basic earnings (loss) per common share (in shares)	51,346		48,185		44,229
Weighted average common shares used in computing diluted earnings (loss) per common share	53,841		53,554		47,638

[1] The sum of the quarterly earnings per share (basic and diluted) may not agree to the earnings per share for the year due to the timing of common stock issuances.