Certain Financial Statement Information - Net Loss Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Schedule of Reconciliation of Shares Used to Calculate Basic and Diluted Net (Loss) Income Per Share
Net loss	$ (8,061)	$ (11,717)	$ (15,465)	$ (24,782)	[1]
Shares used in net loss per share computation:
Weighted average common shares outstanding, basic (shares)	82,176	78,487	81,680	78,202
Net effect of dilutive common share equivalents (shares)	0	0	0	0
Weighted average common shares outstanding, diluted (shares)	82,176	78,487	81,680	78,202
Basic and diluted net loss per share (in dollars per share)	$ (0.10)	$ (0.15)	$ (0.19)	$ (0.32)

[1] The Statement of Cash Flows for the six months ended September 30, 2014 reflects an immaterial revision to correct outstanding payables related to purchases of property and equipment previously included in net cash used for investing activities to net cash used for operating activities. As a result, net cash used for operating activities increased by $0.3 million and net cash used for investing activities decreased by the corresponding amount.