Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2018	Sep. 30, 2017
Current assets:
Cash and cash equivalents	$ 65,477	$ 68,333
Restricted cash	52	421
Accounts receivable, net of allowance of $95 and $22, respectively	17,767	22,265
Inventory	23,726	25,139
Prepaid expenses and other current assets	10,985	8,527
Total current assets	118,007	124,685
Property, plant, and equipment, net	16,728	16,635
Non-current inventory	2,779	2,686
Other non-current assets	791	78
Total assets	138,305	144,084
Current liabilities:
Accounts payable	6,848	11,818
Accrued expenses and other current liabilities	10,626	9,825
Total current liabilities	17,474	21,643
Asset retirement obligations	1,631	1,638
Other long-term liabilities	56	29
Total liabilities	19,161	23,310
Commitments and contingencies (Note 11)
Shareholders’ equity:
Common stock, no par value, 50,000 shares authorized; 34,368 shares issued and 27,458 shares outstanding as of March 31, 2018; 33,938 shares issued and 27,028 shares outstanding as of September 30, 2017	732,055	730,906
Treasury stock at cost; 6,910 shares	(47,721)	(47,721)
Accumulated other comprehensive income	935	561
Accumulated deficit	(566,125)	(562,972)
Total shareholders’ equity	119,144	120,774
Total liabilities and shareholders’ equity	$ 138,305	$ 144,084