Summary of Significant Accounting Policies - Impact of Adoption of ASC 606 on Previously Reported Amounts of Consolidated Statement of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Net loss	$ (103,916)	$ (55,577)
Adjustments to reconcile net loss to net cash used in operating activities:
Deferred revenue	(569)	(1,890)
Cash, cash equivalents and restricted cash, beginning of period	39,992	53,347
Cash, cash equivalents and restricted cash, end of period	55,048	39,992
ASC 606 | As Originally Reported Under ASC 605
Net loss		(57,215)
Adjustments to reconcile net loss to net cash used in operating activities:
Deferred revenue		(252)
Cash, cash equivalents and restricted cash, beginning of period	$ 39,992	53,347
Cash, cash equivalents and restricted cash, end of period		39,992
ASC 606 | Effect of Change
Net loss		1,638
Adjustments to reconcile net loss to net cash used in operating activities:
Deferred revenue		$ (1,638)