Stock-Based Compensation (Tables)

3 Months Ended

Jun. 30, 2014

Stock-Based Compensation [Abstract]

Summary of Award Activity

	Stock						Total
	Options			RSUs			Awards
Outstanding at March 31, 2014		6,774			1,476			8,250
Grants		966			927			1,893
Stock option exercises/vesting RSUs		(198	)		(248	)		(446	)
Retired or forfeited		(312	)		(152	)		(464	)
Outstanding at June 30, 2014		7,230			2,003			9,233
Total shares available for future grant at June 30, 2014								5,653

Schedule of Stock-Based Compensation Expense

	Three Months Ended June 30,
	2014		2013
SG&A:
Stock options	$	1,551	$	1,395
RSUs		1,194		768
ESPP		93		127
Total SG&A		2,838		2,290
R&D:
Stock options		214		196
RSUs		179		102
Total R&D		393		298
Total expense	$	3,231	$	2,588

Weighted Average Assumptions Used to Determine Fair Value of Options Granted

	Three Months Ended June 30,
	2014			2013
Expected term (years)		4.63			4.53
Volatility		59.9	%		72.5	%
Risk-free interest rate		1.55	%		0.71	%
Expected dividend yield		-	%		-	%

Weighted Average Assumptions Used to Determine Fair Value of Options Granted Related to ESPP

	Three Months Ended June 30,
	2014			2013
Expected term (years)		0.5			0.5
Volatility		34.8	%		57.5	%
Risk-free interest rate		0.08	%		0.12	%
Expected dividend yield		-	%		-	%