Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net (loss) income	$ (82)	$ 1,757
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and accretion expense	1,202	758
Stock-based compensation expense	915	772
Provision adjustments related to doubtful accounts	17	0
Provision adjustments related to product warranty	58	88
Net loss on disposal of equipment	107	0
Other	(132)	0
Total non-cash adjustments	2,167	1,618
Changes in operating assets and liabilities:
Accounts receivable	(883)	(2,645)
Inventory	2,169	(4,549)
Other assets	(277)	149
Accounts payable	(4,322)	4,824
Accrued expenses and other current liabilities	(727)	(495)
Total change in operating assets and liabilities	(4,040)	(2,716)
Net cash (used in) provided by operating activities	(1,955)	659
Cash flows from investing activities:
Purchase of equipment	(1,881)	(3,242)
Proceeds from disposal of property, plant and equipment	8	0
Net cash used in investing activities	(1,873)	(3,242)
Cash flows from financing activities:
Proceeds from stock plans	16	104
Tax withholding paid on behalf of employees for stock-based awards	(724)	0
Net cash provided by financing activities	(708)	104
Effect of exchange rate changes on foreign currency	15	352
Net decrease in cash, cash equivalents and restricted cash	(4,521)	(2,127)
Cash, cash equivalents and restricted cash at beginning of period	68,754	64,870
Cash, cash equivalents and restricted cash at end of period	64,233	62,743
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION
Cash paid during the period for interest	16	20
Cash paid during the period for income taxes	33	2
NON-CASH INVESTING AND FINANCING ACTIVITIES
Changes in accounts payable related to purchases of equipment	$ (176)	$ (455)