Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2018	Sep. 30, 2018
Current assets:
Cash and cash equivalents	$ 57,284	$ 63,117
Restricted cash	11	78
Accounts receivable, net of allowance of $322 and $548, respectively	18,362	19,275
Inventory	20,466	20,850
Prepaid expenses and other current assets	13,251	12,730
Total current assets	109,374	116,050
Property, plant, and equipment, net	19,088	18,216
Non-current inventory	1,415	1,433
Other non-current assets	114	199
Total assets	129,991	135,898
Current liabilities:
Accounts payable	10,515	12,997
Accrued expenses and other current liabilities	16,008	14,205
Total current liabilities	26,523	27,202
Asset retirement obligations	1,823	1,809
Other long-term liabilities	89	82
Total liabilities	28,435	29,093
Commitments and contingencies (Note 11)
Shareholders’ equity:
Common stock, no par value, 50,000 shares authorized; 34,578 shares issued and 27,668 shares outstanding as of December 31, 2018; 34,487 shares issued and 27,577 shares outstanding as of September 30, 2018	734,341	734,066
Treasury stock at cost; 6,910 shares	(47,721)	(47,721)
Accumulated other comprehensive income	899	885
Accumulated deficit	(585,963)	(580,425)
Total shareholders’ equity	101,556	106,805
Total liabilities and shareholders’ equity	$ 129,991	$ 135,898