Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2013

Stock-Based Compensation [Abstract]

Schedule of stock options and awards

	March 31,
	2013
Common stock shares available for grant		2,037,130
Common stock options outstanding		3,738,174
Restricted stock awards outstanding		44,000
Restricted stock units outstanding		794,165

Schedule of employee stock purchase plan

	Three Months
	Ended
	March 31,
	2013
Shares purchased under ESPP		16,003
Average price of shares purchased under ESPP	$	4.51
Intrinsic value of shares purchased under ESPP	$	36,727

Schedule of stock options activity

	Three Months			Year
	Ended			Ended
	March 31,			December 31,
	2013			2012
Beginning outstanding balance		3,155,631			3,267,838
Granted		877,500			425,150
Exercised		(273,957	)		(231,403	)
Forfeited and cancelled		(21,000	)		(305,954	)
Ending outstanding balance		3,738,174			3,155,631
Aggregate intrinsic value of options exercised	$	872,353		$	443,000
Weighted average fair value of options granted		5.31			3.35

Schedule of information regarding stock options outstanding

					Weighted
			Weighted		Average		Aggregate
			Average		Remaining		Intrinsic
	Number of		Exercise		Contractual		Value
	Shares		Price		Life (years)		(In millions)
December 31, 2012
Options outstanding		3,155,631	$	6.65		5.24	$	3.5
Options vested and expected to vest using estimated forfeiture rates		3,019,979		6.67		5.17		3.4
Options exercisable		2,329,987		6.91		4.69		2.5
March 31, 2013
Options outstanding		3,738,174	$	7.33		5.59	$	17.2
Options vested and expected to vest using estimated forfeiture rates		3,445,934		7.24		5.49		16.2
Options exercisable		2,123,986		6.90		4.71		11.0

Schedule of restricted stock units activity

	Three Months			Year
	Ended			Ended
	March 31,			December 31,
	2013			2012
Beginning outstanding balance		708,651			407,765
Awarded		290,150			555,911
Released		(193,222	)		(203,519	)
Forfeited		(11,414	)		(51,506	)
Ending outstanding balance		794,165			708,651
Weighted average grant date fair value of RSUs granted	$	7.02		$	6.64
Total fair value of RSUs released		1,491,038			1,128,000
Total fair value of RSUs remaining unvested		9,323,497			4,868,000

Schedule of information regarding restricted stock units outstanding

		Weighted
		Average		Aggregate
		Remaining		Intrinsic		Fair
	Number of	Contractual		Value		Value
	Shares	Life (years)		(In millions)		(In millions)
December 31, 2012
RSUs outstanding	708,651		1.09	$	4.9	$	4.9
RSUs vested and expected to vest using estimated forfeiture rates	588,170		1.05		4.0
March 31, 2013
RSUs outstanding	794,165		1.59	$	9.3	$	9.3
RSUs vested and expected to vest using estimated forfeiture rates	638,628		1.38		7.5

Schedule of restricted stock awards activity

	Three Months		Year
	Ended		Ended
	March 31,		December 31,
	2013		2012
Beginning outstanding balance		44,000		18,000
Awarded		0		57,750
Released		0		(31,750	)
Forfeited		0		0
Ending outstanding balance		44,000		44,000
Weighted average grant date fair value of restricted stock awarded	$	0.00	$	5.70
Total fair value of restricted stock awards released		0		171,000

Schedule of stock option and employee stock purchase plan, valuation assumptions

	Three Months Ended
	March 31,
Options	2013			2012
Expected life (in years)		4.7			4.5
Volatility		69	%		71	%
Interest rate		0.8	%		0.8	%
Dividend yield		N/	A		N/	A
Employee Stock Purchase Plan	2013			2012
Expected life (in years)		0.5			0.5
Volatility		66	%		72	%
Interest rate		0.1	%		0.1	%
Dividend yield		N/	A		N/	A

Schedule of stock-based compensation

	Three Months Ended
	March 31,
	2013		2012
	(In thousands)
Statement of Operations Classifications
Sales and marketing	$	163	$	115
Research and development		314		209
General and administrative		560		396
Total	$	1,037	$	720