Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Nov. 28, 2016	Sep. 30, 2016
Assets:
Available-for-sale securities	$ 2,577		$ 6,135
Fair Value, Measurements, Recurring
Assets:
Cash equivalents	45		143
Available-for-sale securities	2,577		6,135
Foreign exchange contracts	102		5
Total Assets	2,724		12,102
Liabilities:
Contingent consideration			500
Foreign exchange contracts	113		97
Total Liabilities	113		597
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Measurements, Recurring
Assets:
Cash equivalents			98
Total Assets			98
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring
Assets:
Cash equivalents	45		45
Available-for-sale securities	2,577		6,135
Foreign exchange contracts	102		5
Total Assets	2,724		6,185
Liabilities:
Foreign exchange contracts	113		97
Total Liabilities	113		97
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring
Assets:
Total Assets			5,819
Liabilities:
Contingent consideration			500
Total Liabilities			500
Convertible Debt Securities | Fair Value, Measurements, Recurring
Assets:
Convertible debt securities			5,774
Convertible Debt Securities | Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring
Assets:
Convertible debt securities		$ 5,600	5,774
Warrants
Assets:
Stock warrant	$ 0
Warrants | Fair Value, Measurements, Recurring
Assets:
Stock warrant			45
Warrants | Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring
Assets:
Stock warrant			$ 45