Changes in Stockholders' Equity and Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Oct. 01, 2016	Sep. 30, 2017	Oct. 01, 2016	Dec. 31, 2016
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			$ 270,430
Net loss for the nine months ended September 30, 2017	$ (43,052)	$ (12,414)	(63,349)	$ (45,935)
Unrealized loss related to marketable securities, net of tax			(72)
Recognized loss on redemption of marketable securities, previously unrealized			237
Translation adjustments, net of tax			1,381
Common stock issued in connection with the exercise of stock options, ESPP and vested RSUs, net of tax			665
Stock-based compensation related to stock options, ESPP and RSUs			9,402
Defined benefit pension, net of actuarial losses	0	$ 0	(47)	$ 141
Accounting method transition adjustment					$ (355)
Ending balance	218,292		218,292
Common stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			1,216
Common stock issued in connection with the exercise of stock options, ESPP and vested RSUs, net of tax			15
Ending balance	1,231		1,231
Additional Paid-in capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			680,315
Common stock issued in connection with the exercise of stock options, ESPP and vested RSUs, net of tax			650
Stock-based compensation related to stock options, ESPP and RSUs			9,402
Ending balance	690,367		690,367
Accumulated deficit
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			(406,945)
Net loss for the nine months ended September 30, 2017			(63,349)
Accounting method transition adjustment					$ (355)
Ending balance	(470,649)		(470,649)
Accumulated other comprehensive loss
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance			(4,156)
Unrealized loss related to marketable securities, net of tax			(72)
Recognized loss on redemption of marketable securities, previously unrealized			237
Translation adjustments, net of tax			1,381
Defined benefit pension, net of actuarial losses			(47)
Ending balance	$ (2,657)		$ (2,657)
Hyderabad | Disposed of by Sale
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Ownership percentage	100.00%		100.00%
June 2017 Plan
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation related to stock options, ESPP and RSUs			$ 100