Summary of Significant Accounting Policies - Additional Information (Details)	3 Months Ended				12 Months Ended
	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2019 USD ($) Segment	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Jan. 01, 2019 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Number of reportable and operating segment | Segment					1
Revenue recognized	$ 12,400,000	$ 9,188,000	$ 6,639,000	$ 5,331,000	$ 0	$ 33,558,000	$ 11,442,000
Operating lease, liability					383,000
Deferred rent	$ 200,000					$ 200,000
Operating lease right-of-use assets					$ 417,000			$ 1,940,000
ASU 842
Summary Of Significant Accounting Policies [Line Items]
Operating lease, liability								2,100,000
Operating lease, Right of use asset, before reclassification								2,100,000
Operating lease right-of-use assets								$ 1,900,000