Fair Value Measurements - Schedule of Financial Assets Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Asset
Cash and cash equivalents (money market funds)	$ 63,434	$ 90,549
Short-term investments	135,979
Total financial assets	199,413	90,549
Liability
Warrants	5,465
Total financial liabilities	5,465
Quoted Prices in Active Markets for Identical Assets (Level 1)
Asset
Cash and cash equivalents (money market funds)	63,434	90,549
Short-term investments	135,979
Total financial assets	199,413	$ 90,549
Significant Other Observable Inputs (Level 3)
Liability
Warrants	5,465
Total financial liabilities	$ 5,465