Stockholders' Equity - Common Shares Reserved for Issuance (Details)	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2012
Class of Stock [Line Items]
Options granted and outstanding	1,794,000	2,409,000	3,492,000	4,164,000
Employee Stock Purchase Plan	1,794,000	2,409,000	3,492,000	4,164,000
Common stock reserved for issuance	10,291,000
Stock Options
Class of Stock [Line Items]
Options granted and outstanding	1,794,000
Employee Stock Purchase Plan	1,794,000
Restricted Stock Units (RSUs)
Class of Stock [Line Items]
Restricted Stock Units granted and outstanding	4,328,000
Options and Restricted Stock Units
Class of Stock [Line Items]
Options and RSUs authorized for future grants	2,330,000
Employee Stock Purchase Plan
Class of Stock [Line Items]
Options granted and outstanding	1,839,000
Employee Stock Purchase Plan	1,839,000