Fair Value Measurements - Quantitative Information about Level 3 Fair Value Measurements (Details)	Jun. 30, 2020 USD ($)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Valuation Adjustment For Level Three Asset and Liability	$ 5,100,000
Auction rate securities
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Valuation Adjustment For Level Three Asset and Liability	4,800,000
Auction Rate Securities Purchase Commitment
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Valuation Adjustment For Level Three Asset and Liability	$ 332,000