Summary of Significant Accounting Policies - Net Revenue Disaggregated by Sales Channel and Geographic Region (Details) - USD ($) $ in Thousands	12 Months Ended		39 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Disaggregation Of Revenue [Line Items]
Total net revenue	$ 114,451	$ 73,279	$ 6,200
Direct
Disaggregation Of Revenue [Line Items]
Total net revenue	111,358	69,055
Wholesale
Disaggregation Of Revenue [Line Items]
Total net revenue	1,408	3,728
Managed SaaS
Disaggregation Of Revenue [Line Items]
Total net revenue	1,685	496
North America
Disaggregation Of Revenue [Line Items]
Total net revenue	114,261	73,046
North America | Direct
Disaggregation Of Revenue [Line Items]
Total net revenue	111,168	68,884
North America | Wholesale
Disaggregation Of Revenue [Line Items]
Total net revenue	1,408	3,666
North America | Managed SaaS
Disaggregation Of Revenue [Line Items]
Total net revenue	1,685	496
Other
Disaggregation Of Revenue [Line Items]
Total net revenue	190	233
Other | Direct
Disaggregation Of Revenue [Line Items]
Total net revenue	$ 190	171
Other | Wholesale
Disaggregation Of Revenue [Line Items]
Total net revenue		$ 62