Stockholders' Equity - Employee Stock Purchase Plan (Details) - Employee Stock [Member] - 2012 Employee Stock Purchase Plan - USD ($) $ / shares in Units, shares in Millions, $ in Millions	6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Class of Stock [Line Items]
Common stock reserved for issuance (in shares)	6.8
Maximum percentage of base salary that can be contributed to purchase common stock	20.00%
Percentage of purchase price of common stock equal to fair market value	85.00%
Shares available for future issuance (in shares)	3.9
Employee Stock Purchase Plan (ESPP), Shares Purchased	0.3	0.2
Employee Stock Purchase Plan (ESPP), Average Purchase Price of Shares Purchased	$ 4.73	$ 4.46
Employee Stock Purchase Plan (ESPP), Intrinsic Value of Shares Purchased	$ 0.6	$ 0.4