v2.4.0.8

Summary of Difference Between Tax Derived by Applying Federal Statutory Income Tax Rate (Detail) (USD $) In Thousands, unless otherwise specified | 3 Months Ended | 12 Months Ended
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Apr. 30, 2014 | Jan. 31, 2014 | Oct. 31, 2013 | Jul. 31, 2013 | Apr. 30, 2013 | Jan. 31, 2013 | Oct. 31, 2012 | Jul. 31, 2012 | Apr. 30, 2014 | Apr. 30, 2013 | Apr. 30, 2012
Reconciliation of Statutory Federal Tax Rate [Line Items] |  |  |  |  |  |  |  |  |  |  |
U.S. federal taxes at statutory rate |  |  |  |  |  |  |  |  | $ (18,138) | $ (16,550) | $ (7,996)
State tax provision |  |  |  |  |  |  |  |  | (1,510) | 250 | 237
Foreign tax rate differentials |  |  |  |  |  |  |  |  | (123) | (185) | (110)
Research and development credit |  |  |  |  |  |  |  |  | (1,201) | (1,198) | (613)
Stock options |  |  |  |  |  |  |  |  | 1,608 | 3,752 | 1,448
Nondeductible legal expenses |  |  |  |  |  |  |  |  | 5,796 | 3,956 |
Permanent differences and other |  |  |  |  |  |  |  |  | (1,389) | 153 | 382
Change in valuation allowance |  |  |  |  |  |  |  |  | 14,457 | 8,650 | 7,463
Provision for (benefit from) income taxes | $ (418) | $ 179 | $ 130 | $ (391) | $ 583 | $ (2,295) | $ 271 | $ 269 | $ (500) | $ (1,172) | $ 811

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- Definition Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(h)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 08 -Paragraph h -Article 4 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Income Tax Expense (or Benefit) -URI http://asc.fasb.org/extlink&oid=6515339 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (a),(b) -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32639-109319 + Details
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- Definition The amount of income tax expense or benefit for the period computed by applying the domestic federal statutory tax rates to pretax income from continuing operations. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32687-109319 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 13 -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32698-109319 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 08 -Paragraph h -Subparagraph 2 -Article 4 + Details
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- Definition Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to other nondeductible expenses. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32687-109319 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 13 -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32698-109319 + Details
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