Stock-Based Compensation - (Tables)

12 Months Ended

Dec. 31, 2014

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

A summary of the stock option activity for the Company for the years ended December 31, 2014 and 2013 is as follows:



	Shares		Weighted - Average Exercise Price		Weighted - Average Remaining Contractual Term	Aggregate Intrinsic Value
					(Years)	($000's)
Outstanding - December 31, 2013	1,572,626		$	6.17	7.17	$	27,413
Options granted	984,159		30.39
Options exercised	(652,605	)	3.62
Options forfeited	(22,811	)	26.59
Outstanding - December 31, 2014	1,881,369		$	19.30	8.21	$	26,484
Options vested and expected to vest:
At December 31, 2013	1,519,889		$	6.17	7.17	$	26,716
At December 31, 2014	1,778,371		$	19.30	8.21	$	25,502
Options exercisable:
At December 31, 2013	1,223,533		$	3.65	7.17	$	24,306
At December 31, 2014	786,473		$	8.94	8.21	$	18,898

Schedule of Stock Options Valuation Assumptions

The fair value of stock option grants has been estimated at the date of grant using the Black-Scholes option pricing model with the following weighted average assumptions:



	Years Ended December 31,
	2014		2013		2012
Expected dividend yield	—	%	—	%	—	%
Volatility	48.41		52.02		54.77
Risk-free rate of return	0.19		0.17		0.44
Expected life	6 years		6 years		6 years

Schedule of Grant Date Fair Value and Grant Date Intrinsic Value

Additional information regarding options is as follows (in thousands except for per share amounts):



	Years Ended December 31,
	2014		2013
Weighted-average grant date fair value per share of options granted during the period	$	15.16	$	7.08
Aggregate intrinsic value of options exercised during the period	$	17,465	$	307

Schedule of Restricted Stock Units Activity

A summary of the restricted stock unit activity for the Company for the year ended December 31, 2014 is as follows:



	Units	Weighted - Average Grant Date Fair Value Per Share		Weighted - Average Remaining Contractual Term	Aggregate Intrinsic Value
				(Years)	($000's)
Unvested - December 31, 2013	—	$	—	0.0	$	—
Restricted stock units granted	99,500	27.06
Restricted stock units vested	—	—
Restricted stock units forfeited	—	—
Unvested - December 31, 2014	99,500	$	27.06	2.94	$	3,000

Schedule of Company's Stock-based Compensation Expense

The Company’s stock-based compensation expense related to employee stock options, restricted stock units and ESPP awards for the years ended December 31, 2014, 2013 and 2012 was as follows (in thousands):



	Years Ended December 31,
	2014		2013		2012
Research and development	$	572	$	153	$	48
Sales and marketing	2,930		786		181
General and administrative	1,723		330		66
Total	$	5,225	$	1,269	$	295