Stock-Based Compensation (Tables)

3 Months Ended

Jun. 30, 2018

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Stock-Based Compensation Recognized

The following table summarizes stock-based compensation expense by financial statement line item in the Company’s condensed consolidated statements of operations for the three months ended June 30, 2018 and 2017:

	For the Three Months Ended June 30,
		2018		2017
	(in $000's)
Cost of product revenue	$	575	$	359
Research and development		1,966		1,339
Selling, general and administrative		9,704		6,958
	$	12,245	$	8,656

Summary of Stock Option Activity

The following table summarizes the stock option activity for the three months ended June 30, 2018:

						Weighted
				Weighted		Average		Aggregate
				Average		Remaining		Intrinsic
	Options			Exercise		Contractual		Value
	(in thousands)			Price		Term (years)		(in thousands)
Outstanding at beginning of period		1,282		$	46.18		5.31
Granted		72			383.44
Exercised		(282	)		20.53
Cancelled and expired		(4	)		112.32
Outstanding at end of period		1,068		$	76.20		6.02	$	355,461
Exercisable at end of period		780		$	36.08		5.03	$	290,953
Options vested and expected to vest at end of period		1,048		$	76.12		5.99	$	348,886

Summary of Weighted Average Grant-Date Fair Values And Weighted Average Assumptions Used to Calculate Fair Value of Options Granted

The weighted average grant-date fair values and weighted average assumptions used in the calculation of fair value of options granted during the three months ended June 30, 2018 and 2017 was as follows:

	For the Three Months Ended June 30,
		2018			2017
Weighted average grant-date fair value	$	142.51		$	49.04
Valuation assumptions:
Risk-free interest rate		2.93	%		1.84	%
Expected option life (years)		4.04			4.07
Expected volatility		42.6	%		43.7	%

Summary of Restricted Stock Units Activity

The following table summarizes activity of restricted stock units for the three months ended June 30, 2018:

	Number of Shares			Weighted Average Grant Date Fair Value
	(in thousands)			(per share)
Restricted stock units at beginning of period		880		$	109.01
Granted		183		$	378.88
Vested		(385	)	$	101.74
Forfeited		(7	)	$	145.52
Restricted stock units at end of period		671		$	186.48