Fair Value Measurements - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Sep. 30, 2019
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Estimated fair value of the convertible notes		$ 187.9
Non-vested restricted stock units
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Weighted-average of remaining vesting period	2 years 6 months
Level 2
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Estimated fair value of the convertible notes	$ 280.8