Stock-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2018

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

Schedule of share-based compensation, stock options, activity

The following table summarizes stock option activity during the six months ended June 30, 2018:

	Number of Shares		Weighted Average Exercise Price
Outstanding at December 31, 2017	2,490,465		$	9.59
Granted	—		$	—
Exercised	(5,042	)	$	4.33
Cancelled	(33,728	)	$	11.48
Outstanding at June 30, 2018	2,451,695		$	9.58
Vested and expected to vest at June 30, 2018	2,446,937		$	9.57
Exercisable at June 30, 2018	2,353,368		$	9.44

Schedule of share-based compensation, restricted stock units, activity

The Company’s restricted stock unit activity for the six months ended June 30, 2018 and 2017 was as follows:

	Restricted Stock Units
	Number of Shares		Weighted Average Grant Date Fair Value
Unvested at December 31, 2017	2,073,440		$	9.14
Granted	1,677,126		$	4.45
Vested	(548,089	)	$	9.74
Cancelled	(119,547	)	$	9.02
Unvested at June 30, 2018	3,082,930		$	6.49

Schedule of share-based compensation, market based stock units, activity

The Company’s market-based stock unit activity for the six months ended June 30, 2018 was as follows:     

	Market-Based Stock Units
	Number of Shares	Weighted Average Grant Date Fair Value
Unvested at December 31, 2017	233,743	$	10.88
Target units granted	320,000	$	7.19
Unvested at June 30, 2018	553,743	$	8.75

Schedule of share-based compensation, market based stock units, valuation assumptions

The fair value of these market-based stock units was estimated on the date of grant using the Monte Carlo Simulation Valuation Model, which estimates the potential outcome of achieving the market condition based on simulated future stock prices, with the following assumptions for the six months ended June 30, 2018:

	Six Months Ended June 30,
	2018			2017
Expected volatility	65		%	54		%
Risk-free interest rate	2.40		%	1.50		%
Expected dividend	—		%	—		%
Weighted average fair value	$	7.19		$	13.82

Schedule of employee service share-based compensation, allocation of recognized period costs

Stock-based compensation was recognized in the unaudited condensed consolidated statements of comprehensive loss as follows (in thousands):

	Three Months Ended   June 30,				Six Months Ended   June 30,
	2018		2017		2018		2017
Cost of revenue	$	220	$	131	$	407	$	274
Sales and marketing	695		684		1,340		1,359
Research and development	658		754		1,285		1,427
General and administrative	1,502		1,225		2,767		2,542
Total stock-based compensation expense	$	3,075	$	2,794	$	5,799	$	5,602