Commitments and Contingencies - Additional Information (Details)	3 Months Ended		9 Months Ended		12 Months Ended	103 Months Ended
	Sep. 30, 2020 USD ($) ft² numberOfEmployees	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) ft² numberOfEmployees	Sep. 30, 2019 USD ($)	Dec. 31, 2019 USD ($) numberOfEmployees	Sep. 30, 2020 USD ($) ft² numberOfEmployees	Dec. 31, 2017 USD ($) numberOfEmployees	Sep. 30, 2017 USD ($) numberOfEmployees	Jun. 30, 2015 USD ($)	Mar. 31, 2012 USD ($)
Operating Leased Assets [Line Items]
Operating leases, rent expense	$ 2,800,000	$ 1,900,000	$ 6,800,000	$ 5,700,000
Restricted Cash	179,128,000		179,128,000		$ 174,565,000	$ 179,128,000
Grants receivable										$ 16,500,000
Number of employees to be hired per incentive grant agreement | numberOfEmployees							900	900
Minimum cumulative employee compensation, recapture period one								$ 108,000,000.0
Minimum cumulative employee compensation, recapture period three							$ 324,000,000.0
Cumulative compensation expense incurred	144,500,000		144,500,000		120,100,000	144,500,000
Proceeds from government grants						12,000,000.0
Grant agreement, maximum possible repayment amount, recapture period two							2,200,000
Grant agreement, maximum possible repayment amount, recapture period three							$ 2,500,000
Grant agreement, recapture provision repayments	1,500,000		1,500,000			1,500,000
Delaware grant obligation	9,212,000		9,212,000		10,469,000	9,212,000
Managed services liabilities	451,800,000		451,800,000		446,200,000	451,800,000
PPA II | PPA Entities
Operating Leased Assets [Line Items]
Restricted Cash	$ 108,700,000		$ 108,700,000			$ 108,700,000
PPA IIIb | PPA Entities
Operating Leased Assets [Line Items]
Cash and cash equivalents, period increase (decrease)					$ 20,000,000.0
United States, India, South Korea, China and Taiwan
Operating Leased Assets [Line Items]
Area of real estate property | ft²	370,601		370,601			370,601
Delaware
Operating Leased Assets [Line Items]
Number of full time employees | numberOfEmployees	396		396		323	396
PPA V
Operating Leased Assets [Line Items]
PPA expenses			$ 5,700,000		$ 3,500,000
Term loan | PPA V | Term Loan due December 2021, Non-Recourse
Operating Leased Assets [Line Items]
Debt face amount									$ 131,200,000
Letters of Credit | PPA V
Operating Leased Assets [Line Items]
Maximum borrowing capacity	$ 6,200,000		6,200,000			$ 6,200,000			$ 6,400,000
Amount outstanding	$ 5,200,000		$ 5,200,000		$ 5,000,000.0	$ 5,200,000