Summary of Significant Accounting Policies - Summary of Adoption Impact of ASC 326 on Unaudited Condensed Consolidated Balance Sheet (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Jan. 01, 2020	Dec. 31, 2019	Dec. 31, 2018
Assets
Accounts receivable	$ 39,833		$ 42,322
Other non-current assets	11,486		12,121
Equity
Accumulated deficit	(1,629,843)		$ (1,376,142)	$ (1,228,674)
Accounting Standards Update 2016-13 [Member]
Assets
Accounts receivable		$ (404)
Other non-current assets		(75)
Equity
Accumulated deficit		$ (3,665)
Difference Between Guidance in Effect Before and After ASC Three Two Six [Member] | Accounting Standards Update 2016-13 [Member]
Assets
Accounts receivable	41,918
Other non-current assets	12,046
Equity
Accumulated deficit	$ (1,379,807)