Cash, Cash Equivalents and Marketable Securities Available for Sale - Summary of Cash, Cash Equivalents and Marketable Securities Available for Sale (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Sep. 30, 2017
Cash and Cash Equivalents
Cash, cash equivalents and marketable securities [Line Items]
Amortized Cost	$ 90,023	$ 105,618
Fair Value	90,023	105,618
Cash and Cash Equivalents \| Cash
Cash, cash equivalents and marketable securities [Line Items]
Amortized Cost	71,610	90,323
Fair Value	71,610	90,323
Cash and Cash Equivalents \| Money market funds
Cash, cash equivalents and marketable securities [Line Items]
Amortized Cost	13,813	6,471
Fair Value	13,813	6,471
Cash and Cash Equivalents \| Bank Time Deposits
Cash, cash equivalents and marketable securities [Line Items]
Amortized Cost	4,600	8,824
Fair Value	4,600	8,824
Long-term Marketable Securities \| Marketable securities
Cash, cash equivalents and marketable securities [Line Items]
Trading Securities, Cost	14,313	10,788
Debt Securities, Trading, and Equity Securities, FV-NI	$ 18,059	$ 13,791

Cash, cash equivalents and marketable securities

No definition available.

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- Definition

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

+ References

No definition available.

+ Details

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- Definition

This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

+ References

No definition available.

+ Details

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- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in net income (trading) and investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-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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- Definition

Cost of investments in debt and equity securities and other forms of securities that provide ownership interests classified as trading.

+ References

No definition available.

+ Details

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