Stockholders' Equity - Common Shares Reserved for Issuance (Details)	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2011
Class of Stock [Line Items]
Options granted and outstanding	2,409,000	3,492,000	4,164,000	5,390,000
Employee Stock Purchase Plan	2,409,000	3,492,000	4,164,000	5,390,000
Common stock reserved for issuance	9,367,000
Stock Options
Class of Stock [Line Items]
Options granted and outstanding	2,409,000
Employee Stock Purchase Plan	2,409,000
Restricted Stock Units (RSUs)
Class of Stock [Line Items]
Restricted Stock Units granted and outstanding	6,105,000
Options and Restricted Stock Units
Class of Stock [Line Items]
Options and RSUs authorized for future grants	355,000
Employee Stock Purchase Plan
Class of Stock [Line Items]
Options granted and outstanding	498,000
Employee Stock Purchase Plan	498,000