Fair Value Measurements - Additional Information (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Sep. 30, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities	$ 133,308	$ 151,342
Assets held for sale	2,900	0
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value of Liabilities	36	58
Convertible Debt, Fair Value Disclosures	(5,337)
Cash equivalents	11,628	6,404
Available-for-sale securities	133,308	151,342
Foreign exchange contracts	89
Warrants Not Settleable in Cash, Fair Value Disclosure	(59)
Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value of Liabilities	0	0
Convertible Debt, Fair Value Disclosures	0
Cash equivalents	10,133	5,166
Available-for-sale securities	0	0
Warrants Not Settleable in Cash, Fair Value Disclosure	0
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value of Liabilities	36	58
Convertible Debt, Fair Value Disclosures	0
Cash equivalents	1,495	1,238
Available-for-sale securities	133,308	151,342
Foreign exchange contracts	89
Warrants Not Settleable in Cash, Fair Value Disclosure	0
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value of Liabilities	0	0
Contingent consideration	811
Convertible Debt, Fair Value Disclosures	(5,337)
Cash equivalents	0	0
Available-for-sale securities	0	$ 0
Foreign exchange contracts	0
Warrants Not Settleable in Cash, Fair Value Disclosure	(59)
Assets held for sale	2,900
Fair Value, Measurements, Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, Fair Value Disclosure, Nonrecurring	$ 1,000