Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Sep. 30, 2016
Assets:
Available-for-sale securities	$ 6,178	$ 6,135
Fair Value, Measurements, Recurring
Assets:
Cash equivalents	227	143
Available-for-sale securities	6,178	6,135
Foreign exchange contracts	57	5
Convertible debt securities		5,774
Stock warrant		45
Total Assets	6,462	12,102
Liabilities
Contingent consideration		500
Foreign exchange contracts	150	97
Total Liabilities	150	597
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Measurements, Recurring
Assets:
Cash equivalents	183	98
Available-for-sale securities	0	0
Foreign exchange contracts	0	0
Stock warrant		0
Total Assets	183	98
Liabilities
Contingent consideration		0
Foreign exchange contracts	0	0
Total Liabilities	0	0
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring
Assets:
Cash equivalents	44	45
Available-for-sale securities	6,178	6,135
Foreign exchange contracts	57	5
Stock warrant		0
Total Assets	6,279	6,185
Liabilities
Contingent consideration		0
Foreign exchange contracts	150	97
Total Liabilities	150	97
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring
Assets:
Cash equivalents	0	0
Available-for-sale securities	0	0
Foreign exchange contracts	0	0
Convertible debt securities		5,774
Stock warrant		45
Total Assets	0	5,819
Liabilities
Contingent consideration		500
Foreign exchange contracts	0	0
Total Liabilities	$ 0	500
Convertible Debt Securities | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Measurements, Recurring
Assets:
Convertible debt securities		0
Convertible Debt Securities | Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring
Assets:
Convertible debt securities		$ 0