Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Deferred tax assets:
Fixed assets	$ 231	$ 1,156
Net operating loss carryforwards	56,376	47,400
Accruals, reserves and other	12,103	4,940
Foreign tax credit	6,460	6,615
Stock-based compensation	3,830	4,866
Research and development credit	11,190	9,292
Other	2,011	138
Total deferred tax assets	92,201	74,407
Deferred tax liabilities:
Fixed assets	(1)	(290)
Intangible assets	(4,447)	(4,525)
Other		(16)
Net deferred tax assets	87,753	69,576
Less valuation allowance	(87,561)	(69,321)
Net deferred tax liability	192	255
US
Deferred tax assets:
Fixed assets	191
Net operating loss carryforwards	55,850	37,907
Accruals, reserves and other	12,006	4,811
Foreign tax credit	6,460	6,615
Stock-based compensation	3,830	4,866
Research and development credit	11,190	9,292
Other	2,011	121
Total deferred tax assets	91,538	63,612
Deferred tax liabilities:
Fixed assets		(290)
Intangible assets	(4,441)	(4,471)
Net deferred tax assets	87,097	58,851
Less valuation allowance	(87,097)	(58,851)
Foreign
Deferred tax assets:
Fixed assets	40	1,156
Net operating loss carryforwards	526	9,493
Accruals, reserves and other	97	129
Other		17
Total deferred tax assets	663	10,795
Deferred tax liabilities:
Fixed assets	(1)
Intangible assets	(6)	(54)
Other		(16)
Net deferred tax assets	656	10,725
Less valuation allowance	(464)	(10,470)
Net deferred tax liability	$ 192	$ 255