Annual report pursuant to Section 13 and 15(d)

Income taxes - Summary of Income Tax Contingencies (Details)

v3.10.0.1
Income taxes - Summary of Income Tax Contingencies (Details) - USD ($)
$ in Thousands
12 Months Ended
Sep. 30, 2018
Sep. 30, 2017
Sep. 30, 2016
Reconciliation of the beginning and ending amount of gross unrecognized tax benefits      
Balance at beginning of year $ 633 $ 448 $ 529
Increases for tax positions taken in current year 88 185 0
Reductions for tax positions of prior years 0 0 (81)
Balance at end of year $ 721 $ 633 $ 448