Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2019	Sep. 30, 2018
Current assets:
Cash and cash equivalents	$ 50,604	$ 63,117
Restricted cash	33	78
Accounts receivable, net of allowance of $267 and $548, respectively	20,131	19,275
Inventory	20,672	20,850
Prepaid expenses and other current assets	16,392	12,730
Total current assets	107,832	116,050
Property, plant, and equipment, net	21,095	18,216
Non-current inventory	1,114	1,433
Other non-current assets	84	199
Total assets	130,125	135,898
Current liabilities:
Accounts payable	13,321	12,997
Accrued expenses and other current liabilities	17,381	14,205
Total current liabilities	30,702	27,202
Asset retirement obligations	1,836	1,809
Other long-term liabilities	96	82
Total liabilities	32,634	29,093
Commitments and contingencies (Note 12)
Shareholders’ equity:
Common stock, no par value, 50,000 shares authorized; 34,767 shares issued and 27,856 shares outstanding as of March 31, 2019; 34,487 shares issued and 27,577 shares outstanding as of September 30, 2018	735,257	734,066
Treasury stock at cost; 6,910 shares	(47,721)	(47,721)
Accumulated other comprehensive income	912	885
Accumulated deficit	(590,957)	(580,425)
Total shareholders’ equity	97,491	106,805
Total liabilities and shareholders’ equity	$ 130,125	$ 135,898