Stock-based Compensation

6 Months Ended

Jul. 31, 2013

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock-based Compensation

7. Stock-based Compensation

The following table presents the classification of stock-based compensation for the periods indicated:

	Three Months Ended July 31,				Six Months Ended July 31,
	2013		2012		2013		2012
	(in thousands)
Stock-based compensation:
Cost of revenue	$	34	$	15	$	68	$	29
Research and development		900		542		1,874		1,074
Selling, general and administrative		659		456		1,257		853
Total stock-based compensation	$	1,593	$	1,013	$	3,199	$	1,956

As of July 31, 2013, total unrecognized compensation cost related to unvested stock options and unvested restricted stock units was $6.3 million and $1.9 million, respectively, and is expected to be recognized over a weighted-average period of 2.05 years and 1.71 years, respectively. As of January 31, 2013, total unrecognized compensation cost related to unvested stock options and unvested restricted stock units was $7.3 million and $2.4 million, respectively, and is expected to be recognized over a weighted-average period of 2.26 years and 1.77 years, respectively.

The income tax benefit on stock-based compensation recognized for each of the six months ended July 31, 2013 and 2012 was not material.

The following table sets forth the weighted-average assumptions used to estimate the fair value of stock options for the periods indicated:

	Three Months Ended July 31,						Six Months Ended July 31,
	2013			2012			2013			2012
Stock Options:
Volatility		66	%		66	%		65	%		66	%
Risk-free interest rate		1.25	%		0.81	%		1.21	%		0.94	%
Expected term (years)		6.05			6.05			6.05			6.05
Dividend yield		0	%		0	%		0	%		0	%

The following table summarizes stock option activities for the six months ended July 31, 2013:

	Option Outstanding
										Weighted-
								Total Intrinsic		Average
						Weighted-		Value of		Remaining
				Weighted-		Average		options		Contractual		Aggregate
				Average		Grant-date		Exercised		Term		Intrinsic Value
	Shares			Exercise Price		Fair Value		(in thousands)		(in years)		(in thousands)
Outstanding at January 31, 2013		4,344,535			6.07
Granted		138,720			15.22	$	9.05
Exercised		(424,168	)		4.24			$	4,781
Forfeited		(51,165	)		10.28
Outstanding at July 31, 2013		4,007,922			6.52						6.59	$	40,382
Exercisable at July 31, 2013		2,973,868			5.60						6.01	$	32,717
Vested and expected to vest at July 31, 2013		3,945,728			6.48						6.56	$	39,927

Exercisable shares include options with early exercise rights. The vested and expected-to-vest options are calculated based on the vesting schedule of each grant as of the reporting date.

The intrinsic value of options outstanding, exercisable and vested and expected-to-vest are calculated based on the difference between the fair market value of the Company’s ordinary shares on the reporting date and the exercise price. The closing price of the Company’s ordinary shares was $16.60 on July 31, 2013, as reported by the NASDAQ Global Market. The intrinsic value of exercised options is calculated based on the difference between the fair market value of the Company’s ordinary shares on the exercise date and the exercise price.

The following table summarizes restricted stock unit activities for the six months ended July 31, 2013:

				Weighted-
				Average
				Grant-Date
	Shares			Fair Value
Unvested at January 31, 2013		339,217		$	9.99
Granted		27,112			15.29
Released		(62,361	)		9.99
Forfeited		(7,379	)		9.99
Unvested at July 31, 2013		296,589		$	10.47

As of July 31, 2013, the aggregate intrinsic value of unvested restricted stock units was $4.9 million.

Non-employee Stock-based Compensation

The fair value of awards granted to non-employees is determined on the date of grant and remeasured at the end of each reporting period until such awards vest. The non-employee stock-based compensation was not material for the six months ended July 31, 2013 and 2012, respectively.