Annual report pursuant to Section 13 and 15(d)

Income Taxes - Activity Related to Company's Unrecognized Tax Benefits (Detail)

v3.8.0.1
Income Taxes - Activity Related to Company's Unrecognized Tax Benefits (Detail) - USD ($)
$ in Thousands
12 Months Ended
Sep. 30, 2017
Sep. 24, 2016
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]    
Beginning Balance $ 254 $ 138
Increases related to prior year tax positions 4 51
Increases related to current year tax positions 67 66
Decreases related to prior year tax positions 0 0
Settlements 0 (1)
Decreases related to lapse of statute of limitations 0 0
Ending Balance $ 325 $ 254