Stockholders' Equity (Deficit) - Summary of Preferred Stock (Details) - USD ($) $ / shares in Units, $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Temporary Equity [Line Items]
Shares Authorized	0	38,055,000
Shares Issued and Outstanding		37,267,000
Liquidation Preference		$ 138,970
Carrying Value	$ 0	$ 134,720
Series A
Temporary Equity [Line Items]
Shares Authorized		4,367,000
Shares Issued and Outstanding		4,350,000
Per Share Original Issue Price and Conversion Price		$ 2.2615
Liquidation Preference		$ 9,838
Carrying Value		$ 9,773
Series B
Temporary Equity [Line Items]
Shares Authorized		8,108,000
Shares Issued and Outstanding		8,108,000
Per Share Original Issue Price and Conversion Price		$ 2.8269
Liquidation Preference		$ 22,922
Carrying Value		$ 22,814
Series C
Temporary Equity [Line Items]
Shares Authorized		25,580,000
Shares Issued and Outstanding		24,809,000
Per Share Original Issue Price and Conversion Price		$ 4.2812
Liquidation Preference		$ 106,210
Carrying Value		$ 102,133