STOCK PLANS (Tables)

12 Months Ended

Mar. 31, 2019

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 the Company's 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,
	2019		2018		2017
Cost of product revenue	$	1,463	$	1,159	$	934
Cost of service revenue	5,959		4,824		3,956
Research and development	17,321		14,711		12,362
Sales and marketing	18,923		15,213		12,823
General and administrative	12,662		11,410		9,114
	$	56,328	$	47,317	$	39,189

Summary of Transactions under Amended 2007 Equity Incentive Plan

Transactions under the Amended 2007 Plan during the fiscal years ended March 31, 2019, 2018 and 2017 are summarized in the table below.

	Restricted Stock Units
	Number of Awards		Weighted Average Fair Value
Outstanding – March 31, 2016	2,873,306		$	35.32
Granted	2,020,536		24.92
Vested	(950,159	)	33.16
Canceled	(333,382	)	33.40
Outstanding – March 31, 2017	3,610,301		$	30.24
Granted	1,962,590		34.01
Vested	(1,216,585	)	31.09
Canceled	(277,526	)	31.70
Outstanding – March 31, 2018	4,078,780		$	31.77
Granted	2,178,339		30.10
Vested	(1,438,219	)	32.49
Canceled	(608,245	)	30.52
Outstanding – March 31, 2019	4,210,655		$	30.84

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, 2019, 2018 and 2017 were as follows (in thousands):

	Year Ended March 31,
	2019		2018		2017
Total fair value of restricted stock unit awards vested	$	38,070	$	40,539	$	28,293