Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2018	Sep. 30, 2017
Current assets:
Cash and cash equivalents	$ 63,117	$ 68,333
Restricted cash	78	421
Accounts receivable, net of allowance of $548 and $22, respectively	19,275	22,265
Inventory	20,850	25,139
Prepaid expenses and other current assets	12,730	8,527
Total current assets	116,050	124,685
Property, plant, and equipment, net	18,216	16,635
Non-current inventory	1,433	2,686
Other non-current assets	199	78
Total assets	135,898	144,084
Current liabilities:
Accounts payable	12,997	11,818
Accrued expenses and other current liabilities	14,205	9,825
Total current liabilities	27,202	21,643
Asset retirement obligations	1,809	1,638
Other long-term liabilities	82	29
Total liabilities	29,093	23,310
Commitments and contingencies (Note 11)
Shareholders’ equity:
Common stock, no par value, 50,000 shares authorized; 34,487 shares issued and 27,577 shares outstanding as of September 30, 2018; 33,938 shares issued and 27,028 shares outstanding as of September 30, 2017	734,066	730,906
Treasury stock at cost; 6,910 shares	(47,721)	(47,721)
Accumulated other comprehensive income	885	561
Accumulated deficit	(580,425)	(562,972)
Total shareholders’ equity	106,805	120,774
Total liabilities and shareholders’ equity	$ 135,898	$ 144,084