Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2017	Sep. 30, 2016
Current assets:
Cash and cash equivalents	$ 68,333	$ 63,905
Restricted cash	421	965
Accounts receivable, net of allowance of $22 and $36, respectively	22,265	18,432
Inventory	25,139	24,150
Prepaid expenses and other current assets	8,527	3,764
Total current assets	124,685	111,216
Property, plant, and equipment, net	16,635	12,213
Non-current inventory	2,686	3,531
Other non-current assets	78	251
Total assets	144,084	127,211
Current liabilities:
Accounts payable	11,818	10,575
Accrued expenses and other current liabilities	9,825	7,684
Total current liabilities	21,643	18,259
Asset retirement obligations	1,638	1,573
Other long-term liabilities	29	62
Total liabilities	23,310	19,894
Commitments and contingencies (Note 13)
Shareholders’ equity:
Preferred stock, $0.0001 par value, 5,882 shares authorized; none issued or outstanding	0	0
Common stock, no par value, 50,000 shares authorized; 33,938 shares issued and 27,028 shares outstanding as of September 30, 2017; 33,154 shares issued and 26,244 shares outstanding as of September 30, 2016	730,906	725,666
Treasury stock at cost; 6,910 shares	(47,721)	(47,721)
Accumulated other comprehensive income	561	579
Accumulated deficit	(562,972)	(571,207)
Total shareholders’ equity	120,774	107,317
Total liabilities and shareholders’ equity	$ 144,084	$ 127,211