Fair Value Measurements - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Financial instruments transferred among fair value hierarchy levels	$ 0
Cash equivalents included of available-for-sale securities	15,000,000.0	$ 9,100,000
Available for sale securities with contractual maturities of three months to one year.	279,700,000	$ 300,500,000
Available for sale securities with contractual maturities greater than one year	$ 39,400,000