Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2016

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Share Based Fair Value Assumptions

The fair value of options granted were estimated using the Black-Scholes-Merton option pricing model based on the assumptions in the table below:

	Years ended December 31,
	2016		2015		2014
Expected dividend yield		0%		0%		0%
Expected volatility		47%	45% - 56%		46% - 63%
Risk-free interest rate	1.13% - 2.09%		1.44% - 1.95%		1.60% - 2.30%
Expected life (in years)	5.5 - 6.3		5.5 - 6.3		5.2 - 7.0

Schedule of Stock Option Activity

The following table summarizes the Company’s stock option activity, including grants to non-employees, for the year ended December 31, 2016:

						Weighted-
						Average
				Weighted-		Remaining
	Number of			Average		Contractual
	Shares			Exercise Price		Term (Years)
Options outstanding at December 31, 2015		8,300,819		$	2.63		8.23
Granted		5,368,755			2.81
Forfeited		(797,301	)		3.53
Cancelled		(152,946	)		4.61
Exercised		(230,776	)		0.71
Options outstanding at December 31, 2016		12,488,551		$	2.66		8.08

Schedule of Stock Options Outstanding

The following table summarizes information about stock options outstanding at December 31, 2016:

					Weighted
					Average
			Weighted		Remaining
	Number of		Average		Contractual
	Shares		Exercise Price		Term (Years)
Exercisable at December 31, 2016		4,822,183	$	2.43		6.65
Vested or expected to vest at December 31, 2016		11,987,933	$	2.66		8.03