Stock-Based Compensation (Tables)

3 Months Ended

Jun. 30, 2016

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, 2016 and 2015:

	For the Three Months Ended June 30,
		2016		2015
	(in $000's)
Cost of product revenue	$	299	$	237
Research and development		1,255		931
Selling, general and administrative		6,843		3,631
	$	8,397	$	4,799

Summary of Stock Option Activity

The following table summarizes the stock option activity for the three months ended June 30, 2016:

						Weighted
				Weighted		Average		Aggregate
				Average		Remaining		Intrinsic
	Options			Exercise		Contractual		Value
	(in thousands)			Price		Term (years)		(in thousands)
Outstanding at beginning of period		2,244		$	20.55		5.19
Granted		110			99.65
Exercised		(197	)		14.10
Cancelled and expired		(3	)		46.63
Outstanding at end of period		2,154		$	25.12		5.42	$	181,299
Exercisable at end of period		1,657		$	16.00		4.48	$	154,565
Options vested and expected to vest at end of period		2,100		$	24.53		5.34	$	178,007

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, 2016 and 2015 was as follows:

	For the Three Months Ended June 30,
		2016			2015
Weighted average grant-date fair value	$	40.33		$	27.33
Valuation assumptions:
Risk-free interest rate		1.38	%		1.57	%
Expected option life (years)		4.13			4.15
Expected volatility		49.8	%		50.4	%

Restricted Stock Units

Summary of Restricted Stock Units Activity

The following table summarized activity of restricted stock units for the three months ended June 30, 2016:

	Number of Shares			Weighted Average Grant Date Fair Value
	(in thousands)			(per share)
Restricted stock and restricted stock units at beginning of    period		1,263		$	57.95
Granted		254		$	98.45
Vested		(373	)	$	32.40
Forfeited		(5	)	$	28.87
Restricted stock and restricted stock units at end of period		1,139		$	75.70