Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Income Statement [Abstract]
Revenues, net of returns and allowances	$ 29,135	$ 22,074
Cost of sales	20,692	16,119
Gross profit	8,443	5,955
Selling, general and administrative	6,996	7,596
Research, development and engineering	1,627	2,288
Operating loss	(180)	(3,929)
Loss from equity method investment	(143)	(17)
Interest expense and other income, net	81	(202)
Loss before income taxes	(242)	(4,148)
Income tax provision	90	300
Net loss	(332)	(4,448)
Add: net loss attributable to noncontrolling interest	279	433
Net loss attributable to Amtech Systems, Inc.	$ (53)	$ (4,015)
Loss Per Share:
Basic loss per share attributable to Amtech shareholders (USD per share)	$ 0.00	$ (0.31)
Weighted average shares outstanding (in shares)	13,179	13,152
Diluted loss per share attributable to Amtech shareholders (dollars per share)	$ 0.00	$ (0.31)
Weighted average shares outstanding (in shares)	13,179	13,152