Balance Sheet Components - Prepaid Expense and Other Current Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2020		Dec. 31, 2019		Jun. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Government incentives receivable	$ 832		$ 893
Prepaid maintenance	3,158		3,763
Receivables from employees	6,089		6,130
Other prepaid expenses and other current assets	10,668		17,282
Prepaid expenses and other current assets	$ 20,747	[1]	$ 28,068	[1]	$ 26,483

[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).