Earnings per share (Tables)

6 Months Ended

Jun. 30, 2012

Earnings Per Share [Abstract]

Schedule of computation of basic earnings per share

	Three Months Ended June 30,						Six Months Ended June 30,
	2012			2011			2012			2011
Basic earnings (loss) per share:
Net income (loss)	$	7,288		$	3,776		$	11,433		$	(3,138	)
Redeemable convertible preferred stock dividends	(2,936		)	(2,936		)	(5,872		)	$	(5,872	)
Deemed dividend resulting from modification of redeemable convertible preferred stock	$	(2,929	)	$	—		$	(2,929	)	$	—
Net income (loss) attributable to common stockholders—Basic	$	1,423		$	840		$	2,632		$	(9,010	)
Weighted average common shares outstanding	7,049,863			7,505,505			7,043,571			7,451,737
Basic earnings (loss) per share	$	0.20		$	0.11		$	0.37		$	(1.21	)

Schedule of computation of diluted earnings per share

	Three Months Ended June 30,				Six Months Ended June 30,
	2012		2011		2012		2011
Diluted earnings (loss) per share:
Net income (loss) attributable to common stockholders—Diluted	$	7,288	$	3,776	$	11,433	$	(9,010	)
Weighted average common shares outstanding	7,049,863		7,505,505		7,043,571		7,451,737
Options to purchase common stock	4,602,055		3,082,612		3,954,035		—
Convertible preferred stock (as converted basis)	26,767,656		26,767,656		26,767,656		—
Contingent preferred stock per Election and Amendment Agreement (1)	151,111		—		151,111		—
Convertible preferred stock warrants (as converted basis)	50,009		35,757		42,996		—
Weighted average shares and potential diluted shares	38,620,694		37,391,530		37,959,369		7,451,737
Diluted earnings (loss) per share	$	0.19	$	0.10	$	0.30	$	(1.21	)

(1) Additional preferred stock per Election and Amendment Agreement as discussed in “-Note 11-Redeemable Convertible Preferred Stock." Shares calculated based on common stock fair value of $26.50 as of June 30, 2012.

Schedule of anti-dilutive securities excluded from computation of earnings per share

The potentially dilutive securities that have been excluded from the calculation of diluted net income (loss) per common share because the effect is anti-dilutive is as follows:

	Three Months Ended June 30,		Six Months Ended June 30,
	2012	2011	2012	2011
Options to purchase common stock	4,639,939	5,953,591	5,287,959	9,036,203
Convertible preferred stock (as converted basis)	—	—	—	26,767,656
Convertible preferred stock warrants (as converted basis)	53,895	68,147	60,908	103,904
	4,693,834	6,021,738	5,348,867	35,907,763