Summary of Significant Accounting Policies - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jan. 01, 2019	Oct. 31, 2018
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Restricted cash	$ 0	$ 0
Allowance for doubtful accounts	0	0
Contract asset	6,200,000			$ 4,900,000
Advertising expense	1,300,000	200,000	$ 300,000
Payment of offering costs related to initial public offering	723,000	4,386,000	$ 0
Deferred revenue	12,300,000	16,100,000
Deferred revenue, revenue recognized	15,200,000
Right-of-use assets	29,140,000			14,500,000
Operating lease, liability	40,396,000			22,400,000
Additional Paid-in Capital
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Deferred offering costs					$ 4,500,000
ASU 2018-07 adoption
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Cumulative effect of new accounting principle				0
ASU 2018-07 adoption | Additional Paid-in Capital
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Cumulative effect of new accounting principle				1,266,000
ASU 2018-07 adoption | Accumulated Deficit
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Cumulative effect of new accounting principle				$ (1,266,000)
Collaborative Arrangement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Deferred revenue	$ 4,800,000	$ 10,500,000
Minimum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Intangible assets, useful life	6 years
Maximum
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Intangible assets, useful life	10 years
Other Assets
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Contract asset	$ 1,000,000.0