Stockholders' Equity (Tables)

9 Months Ended

Sep. 30, 2017

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

Weighted Average Assumptions of Fair Value Options Using Black-Scholes Option-Pricing Model

The fair value of each option grant is estimated on the date of grant using the Black-Scholes option-pricing model with the following weighted average assumptions:

	Three Months Ended		Nine Months Ended
	September 30,		September 30,
	2017	2016	2017	2016
Dividend yield	0.0%	0.0%	0.0%	0.0%
Risk-free interest rate	1.8%	1.1%	1.7% - 1.9%	1.0% - 1.4%
Expected life (in years)	5	5	5	5
Historical volatility	47.3%	47.9%	46.6% - 47.6%	47.3% - 48.2%

Summary of Stock Option Activity and Weighted Average Exercise Prices

A summary of the Company’s stock option activity and weighted average exercise prices follows:

	Stock Option Activity				Weighted Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value (in thousands)
	Options (in thousands)		Weighted Average Exercise Price
Balance outstanding at December 31, 2016	7,769		$	10.88
Granted	1,553		8.47
Exercised	(777	)	8.86
Cancelled or expired	(841	)	12.14
Balance outstanding at September 30, 2017	7,704		$	10.47	6.14	$	26,888
Options vested and expected to vest	7,045		$	10.66	5.85	$	23,517
Options exercisable at September 30, 2017	5,151		$	11.18	4.86	$	15,315

Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range

The following table summarizes information about outstanding and vested stock options as of September 30, 2017:

	Options Outstanding				Options Exercisable
Range of Exercise Prices	Number of Shares Outstanding (in thousands)	Weighted-Average Remaining Contractual Life (Years)	Weighted-Average Exercise Price		Number of Shares (in thousands)	Weighted-Average Exercise Price
$1.79 - $7.02	892	3.79	$	5.23	674	$	4.81
$7.04 - $7.45	356	7.81	7.26		227	7.22
$7.60 - $7.60	875	9.59	7.60		—	—
$7.95 - $9.24	775	6.28	8.97		601	9.16
$9.34 - $10.05	853	7.53	9.75		502	9.82
$10.13 - $10.31	781	6.12	10.14		585	10.13
$10.53 - $11.96	795	6.68	11.03		394	11.17
$12.09 - $13.28	1,041	4.20	13.05		997	13.04
$13.34 - $16.98	1,042	5.50	15.24		877	15.56
$17.88 - $18.24	294	4.33	18.06		294	18.06
	7,704	6.14	$	10.47	5,151	$	11.18

Schedule of Share-based Compensation, Restricted Stock and Restricted Stock Units Activity

A summary of the Company’s restricted stock units (“RSUs”) activity and weighted average exercise prices follows:

	Restricted Stock Unit Activity
	Number of Shares (in thousands)		Weighted Average Grant Date Fair Value (Per Share)		Aggregate Fair Value (in thousands)
Balance outstanding at December 31, 2016	1,188		$	8.44	$	—
Awarded	317		7.87		—
Released	(312	)	8.40		—
Forfeited	(244	)	8.46		—
Non-vested and outstanding at September 30, 2017	949		$	8.24	$	12,865
Expected to vest	719		$	8.44	$	9,744