Commitments and Contingencies - Additional Information (Details)	12 Months Ended			76 Months Ended
	Dec. 31, 2018 USD ($) ft² employee	Dec. 31, 2017 USD ($) employee	Dec. 31, 2016 USD ($)	Jun. 30, 2018 USD ($)	Jan. 31, 2019 ft²	Feb. 28, 2017 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2012 USD ($) employee
Operating Leased Assets [Line Items]
Operating leases, rent expense	$ 6,300,000	$ 5,200,000	$ 5,100,000
Sale leaseback rent expense	0	0	0
Grants receivable								$ 16,500,000
Number of employees to be hired per incentive grant agreement | employee								900
Minimum cumulative employee compensation, recapture period one								$ 108,000,000
Minimum cumulative employee compensation, recapture period three								324,000,000
Cumulative compensation expense incurred	86,000,000	69,300,000
Proceeds from government grants				$ 12,000,000
Grant agreement, maximum possible repayment amount, recapture period two								5,000,000
Grant agreement, maximum possible repayment amount, recapture period three								$ 2,500,000
Grant agreement, recapture provision repayments	1,500,000	1,500,000
Delaware grant obligation	$ 10,469,000	$ 10,469,000
Self-Generation Incentive Program, percentage of incentive issued in the first year	50.00%
Self-Generation Incentive Program, subsequent payment period	5 years
United States, India, South Korea, China and Taiwan
Operating Leased Assets [Line Items]
Area of real estate property | ft²	487,228
Delaware
Operating Leased Assets [Line Items]
Number of full time employees | employee	335	305
Subsequent Event | San Jose, California
Operating Leased Assets [Line Items]
Area of real estate property | ft²					181,000
PPA Company V
Operating Leased Assets [Line Items]
PPA expenses	$ 900,000	$ 3,700,000	$ 4,800,000
Term loan | PPA Company V | Term Loan due December 2021, Non-Recourse
Operating Leased Assets [Line Items]
Debt face amount							$ 131,200,000
Letters of Credit | PPA Company V
Operating Leased Assets [Line Items]
Maximum borrowing capacity						$ 6,200,000	$ 6,400,000
Amount outstanding	$ 5,000,000	$ 4,400,000