STOCK PLANS (Tables)

12 Months Ended

Mar. 31, 2017

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Summary of Share-Based Compensation Expense

The following is a summary of share-based compensation expense including restricted stock units and employee stock purchases made under our employee stock purchase plan (ESPP) based on estimated fair values within the applicable cost and expense lines identified below (in thousands):

	Year Ended March 31,
	2017		2016		2015
Cost of product revenue	$	934	$	645	$	338
Cost of service revenue	3,956		2,601		1,194
Research and development	12,362		9,205		5,505
Sales and marketing	12,823		8,725		4,841
General and administrative	9,114		7,175		4,702
	$	39,189	$	28,351	$	16,580

Summary of Transactions under 1999 Stock Option Plan and 2007 Equity Incentive Plan

Transactions under the 1999 Stock Option Plan and the 2007 Equity Incentive Plan during the fiscal years ended March 31, 2017, 2016 and 2015 are summarized in the table below.

	Stock Options				Restricted Stock Units
	Number of Shares		Weighted Average Exercise Price		Number of Awards		Weighted Average Fair Value
Outstanding – March 31, 2014	31,350		$	5.87	1,738,299		$	21.11
Granted	—		—		1,009,770		36.92
Exercised (Options)/Issued (RSU’s)	(23,850	)	5.87		(728,239	)	18.97
Canceled	(7,500	)	5.87		(90,515	)	21.44
Outstanding – March 31, 2015	—		$	—	1,929,315		$	30.18
Granted	—		—		1,806,490		37.20
Exercised (Options)/Issued (RSU’s)	—		—		(736,170	)	26.52
Canceled	—		—		(126,329	)	34.99
Outstanding – March 31, 2016	—		$	—	2,873,306		$	35.32
Granted	—		—		2,020,536		24.92
Exercised (Options)/Issued (RSU’s)	—		—		(950,159	)	33.16
Canceled	—		—		(333,382	)	33.40
Outstanding – March 31, 2017	—		$	—	3,610,301		$	30.24

Schedule of Aggregate Intrinsic Values of Stock Options and Restricted Stock Units

The aggregate intrinsic value of stock options exercised and the fair value of restricted stock units vested at March 31, 2017, 2016 and 2015 were as follows (in thousands):

	Year Ended March 31,
	2017		2016		2015
Total intrinsic value of stock options exercised	$	—	$	—	$	800
Total fair value of restricted stock unit awards vested	$	28,293	$	25,936	$	31,651