Share-based Compensation (Tables)

12 Months Ended

Dec. 31, 2017

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

Summary of Share-Based Compensation Expense

For the years ended December 31, 2017, 2016 and 2015, the following table presents total share-based compensation expense in each functional line item on the consolidated statements of operations (in thousands):

	Year Ended December 31,
	2017		2016		2015
Cost of revenues	$	182	$	235	$	233
Research and development	749		868		1,003
Sales and marketing	747		707		579
General and administrative	1,901		2,778		2,963
Restructuring charges	169		—		1,572
Total	$	3,748	$	4,588	$	6,350

Share-based Compensation Stock Option Fair Value Assumptions

The following table presents the weighted-average assumptions used in the Hull-White I valuation model and the Black-Scholes valuation model by the Company in calculating the fair value of each Replacement Option and executive bonus stock option, respectively, granted under the 2015 Plan for the year ended December 31, 2015:

	Hull-White I
	Executive		Non-executive		Black-Scholes
Expected dividend yield	—	%	—	%	—	%
Risk-free interest rate	2.1	%	2.1	%	1.4	%
Volatility	64	%	64	%	67	%
Expected term (in years)	n/a		n/a		5.0
Suboptimal exercise factor	2.570		1.626		n/a
Post-vesting termination rate	3	%	3	%	n/a

The following table presents the weighted-average assumptions used in the Black-Scholes valuation model by the Company in calculating the fair value of each stock option granted under the 2009 Plan:

	Year Ended December 31,
	2017		2016		2015
Expected dividend yield	—	%	—	%	—	%
Risk-free interest rate	1.8	%	1.7	%	1.4	%
Volatility	108	%	79	%	69	%
Expected term (in years)	5.0		5.0		4.5

Summary of Stock Option Activity

The following table summarizes the Company’s stock option activity under all plans for the years ended December 31, 2017 and 2016 (dollars in thousands, except per share data):

	Stock Options Outstanding		Weighted-Average Exercise Price Per Option		Weighted-Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value
Outstanding — December 31, 2015	6,084,836		$	3.01
Granted	1,051,550		1.65
Exercised	(78,384	)	1.12
Canceled	(701,799	)	4.35
Outstanding — December 31, 2016	6,356,203		2.64
Granted	3,877,000		1.15
Exercised	(146,039	)	1.11
Canceled	(3,520,681	)	2.69
Outstanding — December 31, 2017	6,566,483		$	1.77	8.18	$	2,460
Vested and Expected to Vest — December 31, 2017	5,815,396		$	1.84	8.03	$	2,132
Exercisable — December 31, 2017	2,202,598		$	2.83	6.12	$	491

Summary of Restricted Stock Unit Activity

A summary of restricted stock unit activity under all plans for the year ended December 31, 2017 is presented below:

	Number of Shares		Weighted-Average Grant-Date Fair Value
Non-vested — December 31, 2016	2,975,800		$	1.87
Granted	1,480,301		1.83
Vested	(1,193,721	)	1.92
Forfeited	(2,206,403	)	1.72
Non-vested — December 31, 2017	1,055,977		$	2.06