Description of Business and Summary of Significant Accounting Policies - Cash and Cash Equivalents and Short-term Investments Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Level 2 securities:
Total cash, cash equivalents and short-term investments	$ 81,100
Cost or Amortized Cost
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash	343
Level 2 securities:
Total cash, cash equivalents and short-term investments	81,149
Cost or Amortized Cost | Money market funds | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Money market funds	80,806
Cost or Amortized Cost | U.S. government and agency securities | Level 2
Level 2 securities:
Cost or Amortized Cost	0
Cost or Amortized Cost | Corporate debt securities | Level 2
Level 2 securities:
Cost or Amortized Cost	0
Total Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash	343	$ 188
Level 2 securities:
Total cash, cash equivalents and short-term investments	81,149	33,666
Total Estimated Fair Value | Money market funds | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Money market funds	80,806	28,957
Total Estimated Fair Value | U.S. government and agency securities | Level 2
Level 2 securities:
Total Estimated Fair Value	0	2,522
Total Estimated Fair Value | Corporate debt securities | Level 2
Level 2 securities:
Total Estimated Fair Value	$ 0	$ 1,999