Balance Sheet Components - Prepaid Expense and Other Current Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2020		Dec. 31, 2019		Sep. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Government incentives receivable	$ 762		$ 893
Prepaid maintenance	3,780		3,763
Receivables from employees	5,413		6,130
Other prepaid expenses and other current assets	20,285		17,282
Prepaid expenses and other current assets	$ 30,240	[1]	$ 28,068	[1]	$ 28,642

[1] We have variable interest entities, which represent a portion of the consolidated balances recorded within these financial statement line items in the condensed consolidated balance sheets (see Note 13, Power Purchase Agreement Programs).