Fair Value Measurements (Details) $ in Thousands	Dec. 31, 2019 USD ($)
Fair value measurements
Marketable securities	$ 37,439
Recurring basis
Fair value measurements
Total assets regularly measured and carried at fair value	37,439
Recurring basis | Commercial paper
Fair value measurements
Marketable securities	11,940
Recurring basis | Corporate bonds
Fair value measurements
Marketable securities	12,010
Recurring basis | U.S. Treasuries
Fair value measurements
Marketable securities	13,489
Recurring basis | Quoted Prices in Active Markets (Level 1)
Fair value measurements
Total assets regularly measured and carried at fair value	13,489
Recurring basis | Quoted Prices in Active Markets (Level 1) | Commercial paper
Fair value measurements
Marketable securities	0
Recurring basis | Quoted Prices in Active Markets (Level 1) | Corporate bonds
Fair value measurements
Marketable securities	0
Recurring basis | Quoted Prices in Active Markets (Level 1) | U.S. Treasuries
Fair value measurements
Marketable securities	13,489
Recurring basis | Significant Other Observable Inputs (Level 2)
Fair value measurements
Total assets regularly measured and carried at fair value	23,950
Recurring basis | Significant Other Observable Inputs (Level 2) | Commercial paper
Fair value measurements
Marketable securities	11,940
Recurring basis | Significant Other Observable Inputs (Level 2) | Corporate bonds
Fair value measurements
Marketable securities	12,010
Recurring basis | Significant Other Observable Inputs (Level 2) | U.S. Treasuries
Fair value measurements
Marketable securities	0
Recurring basis | Significant Unobservable Inputs (Level 3)
Fair value measurements
Total assets regularly measured and carried at fair value	0
Recurring basis | Significant Unobservable Inputs (Level 3) | Commercial paper
Fair value measurements
Marketable securities	0
Recurring basis | Significant Unobservable Inputs (Level 3) | Corporate bonds
Fair value measurements
Marketable securities	0
Recurring basis | Significant Unobservable Inputs (Level 3) | U.S. Treasuries
Fair value measurements
Marketable securities	$ 0