v3.7.0.1

Fair Value of Financial Assets and Liabilities - Summary of Fair Value of Financial Assets and Liabilities (Details) - USD ($) $ in Thousands | Apr. 30, 2017 | Apr. 30, 2016
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Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Cash equivalents: | $ 52,494 | $ 43,963
Short-term investments: | 38,689 | 50,682
Fair value, measurements, recurring |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Cash equivalents: | 6,330 | 5,271
Short-term investments: | 38,689 | 50,682
Total assets | 45,019 | 55,953
Fair value, measurements, recurring | Fair value, inputs, level 1 |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Cash equivalents: | 3,532 | 922
Short-term investments: | 25,418 | 33,600
Total assets | 28,950 | 34,522
Fair value, measurements, recurring | Fair value, inputs, level 2 |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Cash equivalents: | 2,798 | 4,349
Short-term investments: | 13,271 | 17,082
Total assets | 16,069 | 21,431
Fair value, measurements, recurring | Fair value, inputs, level 3 |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Cash equivalents: | 0 | 0
Short-term investments: | 0 | 0
Total assets | 0 | 0
Certificates of deposit | Fair value, measurements, recurring |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Short-term investments: | 1,930 | 7,089
Certificates of deposit | Fair value, measurements, recurring | Fair value, inputs, level 1 |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Short-term investments: | 0 | 0
Certificates of deposit | Fair value, measurements, recurring | Fair value, inputs, level 2 |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Short-term investments: | 1,930 | 7,089
Certificates of deposit | Fair value, measurements, recurring | Fair value, inputs, level 3 |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Short-term investments: | 0 | 0
Commercial paper | Fair value, measurements, recurring |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Cash equivalents: | 2,798 | 4,349
Short-term investments: | 4,206 | 4,043
Commercial paper | Fair value, measurements, recurring | Fair value, inputs, level 1 |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Cash equivalents: | 0 | 0
Short-term investments: | 0 | 0
Commercial paper | Fair value, measurements, recurring | Fair value, inputs, level 2 |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Cash equivalents: | 2,798 | 4,349
Short-term investments: | 4,206 | 4,043
Commercial paper | Fair value, measurements, recurring | Fair value, inputs, level 3 |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Cash equivalents: | 0 | 0
Short-term investments: | 0 | 0
U.S. Treasury securities | Fair value, measurements, recurring |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Short-term investments: | 8,700 | 8,764
U.S. Treasury securities | Fair value, measurements, recurring | Fair value, inputs, level 1 |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Short-term investments: | 8,700 | 8,764
U.S. Treasury securities | Fair value, measurements, recurring | Fair value, inputs, level 2 |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Short-term investments: | 0 | 0
U.S. Treasury securities | Fair value, measurements, recurring | Fair value, inputs, level 3 |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Short-term investments: | 0 | 0
US government agencies debt securities | Fair value, measurements, recurring |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Short-term investments: | 16,718 | 24,836
US government agencies debt securities | Fair value, measurements, recurring | Fair value, inputs, level 1 |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Short-term investments: | 16,718 | 24,836
US government agencies debt securities | Fair value, measurements, recurring | Fair value, inputs, level 2 |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Short-term investments: | 0 | 0
US government agencies debt securities | Fair value, measurements, recurring | Fair value, inputs, level 3 |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Short-term investments: | 0 | 0
Corporate debt securities | Fair value, measurements, recurring |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Short-term investments: | 7,135 | 5,950
Corporate debt securities | Fair value, measurements, recurring | Fair value, inputs, level 1 |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Short-term investments: | 0 | 0
Corporate debt securities | Fair value, measurements, recurring | Fair value, inputs, level 2 |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Short-term investments: | 7,135 | 5,950
Corporate debt securities | Fair value, measurements, recurring | Fair value, inputs, level 3 |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Short-term investments: | 0 | 0
Money market funds | Fair value, measurements, recurring |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Cash equivalents: | 3,532 | 922
Money market funds | Fair value, measurements, recurring | Fair value, inputs, level 1 |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Cash equivalents: | 3,532 | 922
Money market funds | Fair value, measurements, recurring | Fair value, inputs, level 2 |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Cash equivalents: | 0 | 0
Money market funds | Fair value, measurements, recurring | Fair value, inputs, level 3 |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
Cash equivalents: | $ 0 | $ 0

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- Definition Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258 + Details
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- Definition Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Cash -URI http://asc.fasb.org/extlink&oid=6506951 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Cash Equivalents -URI http://asc.fasb.org/extlink&oid=6507016 + Details
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- Definition Amount of investments including trading securities, available-for-sale securities, held-to-maturity securities, and short-term investments classified as other and current. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(2)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(1)(g)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(5)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(6)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(4)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
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