Employee Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2016

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

Summary of Company's Stock Option and Restricted Stock Unit Activity

Stock Options, RSUs and PRSUs

The following table summarizes the Company’s stock option, RSU and PRSU activities during the year ended December 31, 2016 (in thousands, except per share amounts):

			Stock Options Outstanding				Restricted Stock Units * Outstanding
	Shares Available for Grant		Number of Shares		Weighted Average Exercise Price		Number of Units		Weighted Average Grant Date Fair Value
Balance at December 31, 2015	6,150		5,674		$	6.56	2,182		$	6.99
Authorized	2,000		—		—		—		—
Granted	(6,201	)	946		3.19		3,503		3.78
Options exercised	—		(150	)	4.77		—		—
Shares released	—		—		—		(1,480	)	6.57
Forfeited or canceled	1,963		(1,451	)	6.46		(341	)	5.56
Balance at December 31, 2016	3,912		5,019		$	6.01	3,864		$	4.26

* The preceding table includes PRSUs activities during the year ended December 31, 2016.

Summary of Stock Options Outstanding

The following table summarizes information about stock options outstanding as of December 31, 2016 (in thousands, except per share amounts and term):

	Number of Shares	Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value
Vested and expected to vest	4,839	$	6.05	3.8	$	1,930
Exercisable	3,240	6.61		3.0	388

Summary of Restricted Stock Units Outstanding

The following table summarizes information about RSUs and PRSUs outstanding as of December 31, 2016 (in thousands, except term):

	Number of Shares Underlying Restricted Stock Units	Weighted Average Remaining Vesting Period (Years)	Aggregate Fair Value
Vested and expected to vest	3,606	0.6	$	18,031

Schedule of Defined Benefit Plans Disclosures

The table below shows the present value of the Company’s pension obligations as of December 31, 2016 and changes to the Company’s pension obligations (in thousands):

	December 31, 2016
Projected benefit obligation:
Acquired from TVN acquisition	$	5,907
Service cost	217
Interest cost	87
Actuarial losses	279
Curtailment	(1,955		)
Foreign currency translation adjustment	(271		)
As of December 31, 2016	$	4,264
Presented on the Consolidated Balance Sheets under:
Current portion (presented under “Accrued and other current liabilities”)	$	27
Long-term portion (presented under “Other non-current liabilities”)	$	4,237

Schedule of Pension Obligations Assumptions Used

The following assumptions were used in determining the Company’s pension obligation:

	December 31, 2016
Discount rate	1.5	%
Mobility rate	3.0	%
Salary progression rate	2.0	%

Schedule of Expected Benefit Payments

Future benefits expected to be paid in each of the next five years, and in the aggregate for the five year period thereafter are as follows (in thousands):

Years ending December 31,
2017	$	29
2018	29
2019	46
2020	—
2021	66
2022 - 2026	2,015
	$	2,185

Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs

The following table summarizes stock-based compensation expense for all plans (in thousands):

	Year ended December 31,
	2016		2015		2014
Stock-based compensation in:
Cost of revenue	$	1,554	$	1,862	$	2,359
Research and development expense	3,711		4,435		4,844
Selling, general and administrative expense	7,795		9,285		10,084
Total stock-based compensation in operating expense	11,506		13,720		14,928
Total stock-based compensation recognized in net loss	$	13,060	$	15,582	$	17,287

Valuation Assumptions for Stock Options

The Company estimates the fair value of employee stock options and stock purchase rights under the ESPP using a Black-Scholes option valuation model. The value of the stock purchase rights under the ESPP consists of: (1) the 15% discount on the purchase of the stock; (2) 85% of the fair value of the call option; and (3) 15% of the fair value of the put option. The call option and put option were valued using the Black-Scholes option pricing model. At the date of grant, the Company estimated the fair value of each stock option grant and stock purchase right granted under the ESPP using the following weighted average assumptions:

	Employee Stock Options						ESPP
	2016		2015		2014		2016		2015		2014
Expected term (in years)	4.30		4.65		4.70		0.50		0.50		0.50
Volatility	36	%	38	%	40	%	70	%	34	%	32	%
Risk-free interest rate	1.4	%	1.5	%	1.7	%	0.6	%	0.3	%	0.1	%
Expected dividends	0.0	%	0.0	%	0.0	%	0.0	%	0.0	%	0.0	%