Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Income Statement [Abstract]
Revenue, net of returns and allowances	$ 34,798	$ 81,539	$ 246,705
Cost of sales	26,833	59,511	154,881
Write-down of inventory	3,652	10,380	1,167
Losses on inventory purchase commitments	0	2,455	0
Gross profit	4,313	9,193	90,657
Selling, general and administrative	16,830	23,055	43,739
Research and development	6,594	13,694	5,784
Impairment and restructuring charges	883	5,428	0
Expense related to reacquired shares	0	0	2,855
Operating income (loss)	(19,994)	(32,984)	38,279
Interest and other income, net	147	66	30
Income (loss) before income taxes	(19,847)	(32,918)	38,309
Income tax provision (benefit)	1,860	(5,320)	16,190
Net income (loss)	(21,707)	(27,598)	22,119
Add: net loss attributable to noncontrolling interest	1,638	4,567	763
Net income (loss) attributable to Amtech Systems, Inc.	$ (20,069)	$ (23,031)	$ 22,882
Income (Loss) Per Share:
Basic income (loss) per share attributable to Amtech shareholders (dollars per share)	$ (2.11)	$ (2.43)	$ 2.41
Weighted average shares outstanding (in shares)	9,529	9,471	9,480
Diluted income (loss) per share attributable to Amtech shareholders (dollars per share)	$ (2.11)	$ (2.43)	$ 2.34
Weighted average shares outstanding (in shares)	9,529	9,471	9,764