Notes Payable - Convertible Senior Notes - Additional Information (Details) - 2.25% Convertible Senior Notes due 2022 - Convertible Senior Notes - USD ($) $ in Millions	1 Months Ended
	Jun. 30, 2015	Jun. 30, 2022
Notes Payable
Debt issuance costs incurred	$ 11.7
Debt issuance costs allocated to equity components	4.0
Debt issuance costs allocated to liability components	$ 7.7
Debt instrument term	7 years
Effective interest rate on liability components		2.70%