Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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Stock-Based Compensation - Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Employee and non-employee stock options
Stock based compensation expense
Options granted (in shares)			446,000
Stock-based compensation expense	$ 11,957	$ 5,804	$ 19,374	$ 9,855
Unrecognized compensation expense	95,700		$ 95,700
Unrecognized compensation expense, weighted average period of recognition			2 years 10 months 24 days
Employee and non-employee stock options \| Cost of revenues
Stock based compensation expense
Stock-based compensation expense	441	225	$ 755	393
Employee and non-employee stock options \| Research and development
Stock based compensation expense
Stock-based compensation expense	2,913	1,264	4,755	2,157
Employee and non-employee stock options \| Selling, general and administrative
Stock based compensation expense
Stock-based compensation expense	8,603	4,315	13,864	7,305
Employee stock options
Stock based compensation expense
Stock-based compensation expense	11,599	5,705	18,847	9,413
Employee stock options \| Cost of revenues
Stock based compensation expense
Stock-based compensation expense	441	215	755	383
Employee stock options \| Research and development
Stock based compensation expense
Stock-based compensation expense	2,631	1,264	4,313	2,157
Employee stock options \| Selling, general and administrative
Stock based compensation expense
Stock-based compensation expense	$ 8,527	4,226	$ 13,779	6,873
Non-employee stock options
Stock based compensation expense
Options granted (in shares)			65,485
Options unvested (in shares)	20,262		20,262
Stock-based compensation expense	$ 358	99	$ 527	442
Non-employee stock options \| Cost of revenues
Stock based compensation expense
Stock-based compensation expense		10		10
Non-employee stock options \| Research and development
Stock based compensation expense
Stock-based compensation expense	282		442
Non-employee stock options \| Selling, general and administrative
Stock based compensation expense
Stock-based compensation expense	$ 76	$ 89	$ 85	$ 432