Stockholders' Equity (Details) - shares shares in Millions	Jun. 30, 2017	Jun. 30, 2016	Apr. 17, 2014	Feb. 28, 2013	Aug. 01, 2011
Stockholders' equity
Number of shares of common stock reserved for issuance under stock incentive plans and employee stock purchase plan	7.7
3.75% Convertible Notes
Stockholders' equity
Interest rate (as a percent)	3.75%	3.75%			3.75%
3.50% Convertible Notes
Stockholders' equity
Authorized common stock reserved for future issuance (in shares)	13.2
Interest rate (as a percent)	3.50%	3.50%	3.50%	3.50%