Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2010
Income Statement [Abstract]
Revenues, net of returns and allowances	$ 81,539	$ 246,705	$ 120,019
Cost of sales	59,511	154,881	76,725
Write-down of inventory	10,380	1,167	582
Losses on inventory purchase commitments	2,455	0	0
Gross profit	9,193	90,657	42,712
Selling, general and administrative	23,055	43,739	24,075
Research and development	13,694	5,784	2,118
Impairment charges	5,428	0	610
Expense related to reacquired shares	0	2,855	0
Operating income (loss)	(32,984)	38,279	15,909
Interest and other income (expense), net	66	30	(196)
Income (loss) before income taxes	(32,918)	38,309	15,713
Income tax provision (benefit)	(5,320)	16,190	6,150
Net income (loss)	(27,598)	22,119	9,563
Add: net loss attributable to noncontrolling interest	4,567	763	0
Net income (loss) attributable to Amtech Systems, Inc.	$ (23,031)	$ 22,882	$ 9,563
Income (Loss) Per Share:
Basic income (loss) per share attributable to Amtech shareholders (dollars per share)	$ (2.43)	$ 2.41	$ 1.06
Weighted average shares outstanding (in shares)	9,471	9,480	9,022
Diluted income (loss) per share attributable to Amtech shareholders (dollars per share)	$ (2.43)	$ 2.34	$ 1.04
Weighted average shares outstanding (in shares)	9,471	9,764	9,237