Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Cash flows from operating activities:
Net income	$ 1,757	$ 987
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion expense	758	506
Stock-based compensation expense	772	387
Provision adjustments related to doubtful accounts	0	4
Provision adjustments related to product warranty	88	146
Gain on settlement of solar power assets and obligations	0	(689)
Gain on settlement of Newark lease	0	(310)
Total non-cash adjustments	1,618	44
Changes in operating assets and liabilities:
Accounts receivable	(2,645)	2,877
Inventory	(4,549)	2,115
Other assets	149	1,439
Accounts payable	4,824	(43)
Accrued expenses and other current liabilities	(495)	(1,686)
Total change in operating assets and liabilities	(2,716)	4,702
Net cash provided by operating activities	659	5,733
Cash flows from investing activities:
Purchase of equipment	(3,242)	(1,677)
Net cash used in investing activities	(3,242)	(1,677)
Cash flows from financing activities:
Proceeds from stock plans	104	186
Decrease (increase) in restricted cash	403	(728)
Net cash provided by (used in) financing activities	507	(542)
Effect of exchange rate changes on foreign currency	352	121
Net (decrease) increase in cash and cash equivalents	(1,724)	3,635
Cash and cash equivalents at beginning of period	63,905	111,885
Cash and cash equivalents at end of period	62,181	115,520
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION
Cash paid during the period for interest	20	23
Cash paid during the period for income taxes	2	108
NON-CASH INVESTING AND FINANCING ACTIVITIES
Changes in accounts payable related to purchases of equipment	$ (455)	$ (206)