Condensed Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Jan. 31, 2014	Jan. 31, 2013
Operating activities:
Net loss	$ (39,485)	$ (40,608)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization expense	11,167	7,473
Stock-based expense	10,996	19,072
Revaluation of contingent consideration	(3,270)
Bad debt expense	1,433	1,643
Excess tax benefit related to stock-based expense	(96)	(365)
Changes in operating assets and liabilities:
Accounts receivable	(15,802)	(10,581)
Prepaid expenses and other current assets	(375)	257
Other non-current assets	(1,473)	1,161
Accounts payable	475	521
Accrued expenses and other current liabilities	(2,214)	7,027
Deferred revenue	(1,185)	4,647
Other liabilities, long-term	(927)	(2,952)
Net cash used in operating activities	(40,756)	(12,705)
Investing activities:
Acquisitions, net of cash acquired, and purchase of intangible asset	(670)	(60,750)
Purchases of property, equipment and capitalized internal-use software development costs	(8,506)	(8,004)
Purchases of short-term investments	(34,517)	(74,578)
Proceeds from maturities of short-term investments	45,410	38,769
Proceeds from sales of short-term investments	31,292	5,014
Net cash provided by (used in) investing activities	33,009	(99,549)
Financing activities:
Proceeds from follow-on stock offering, net of costs		51,943
Proceeds from employee stock compensation plans	11,039	9,470
Excess tax benefit related to stock-based expense	96	365
Net cash provided by financing activities	11,135	61,778
Effect of exchange rate fluctuations on cash and cash equivalents	259	(46)
Net change in cash and cash equivalents	3,647	(50,522)
Cash and cash equivalents at beginning of period	25,045	74,367
Cash and cash equivalents at end of period	28,692	23,845
Supplemental disclosure of other cash flow information:
Cash paid for income taxes	730	236
Supplemental disclosure of non-cash investing and financing activities:
Issuance of stock for acquisition		$ 125,497