Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018	Sep. 30, 2018
Cash flows from operating activities:
Net loss	$ (4,994)	$ (3,071)	$ (10,532)	$ (3,153)	$ (3,153)
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization expense			3,228	2,605
Stock-based compensation expense			1,147	1,848
Provision adjustments related to doubtful accounts			0	75
Provision adjustments related to product warranty			105	282
Net loss on disposal of equipment			0	39
Other			(316)	(643)
Total non-cash adjustments			4,164	4,206
Changes in operating assets and liabilities:
Accounts receivable			(789)	4,422
Inventory			699	2,041
Other assets			(3,247)	(2,812)
Accounts payable			(265)	(4,923)
Accrued expenses and other current liabilities			2,909	304
Total change in operating assets and liabilities			(693)	(968)
Net cash (used in) provided by operating activities			(7,061)	85
Cash flows from investing activities:
Purchase of equipment			(5,576)	(2,735)
Proceeds from disposal of property, plant and equipment			0	77
Net cash used in investing activities			(5,576)	(2,658)
Cash flows from financing activities:
Proceeds from stock plans			238	442
Tax withholding paid on behalf of employees for stock-based awards			(194)	(1,139)
Net cash provided by (used in) financing activities			44	(697)
Effect of exchange rate changes (used in) provided by foreign currency			35	45
Net decrease in cash, cash equivalents and restricted cash			(12,558)	(3,225)
Cash, cash equivalents and restricted cash at beginning of period			63,195	68,754	68,754
Cash, cash equivalents and restricted cash at end of period	$ 50,637	$ 65,529	50,637	65,529	$ 63,195
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION
Cash paid during the period for interest			56	31
Cash paid during the period for income taxes			59	130
NON-CASH INVESTING AND FINANCING ACTIVITIES
Changes in accounts payable related to purchases of equipment			$ 481	$ (235)