Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016
Income Statement [Abstract]
Revenues, net of returns and allowances	$ 32,944	$ 22,483	$ 62,079	$ 44,557
Cost of sales	24,549	16,482	45,241	32,601
Gross profit	8,395	6,001	16,838	11,956
Selling, general and administrative	8,260	7,448	15,258	15,044
Research, development and engineering	1,535	2,160	3,163	4,447
Operating loss	(1,400)	(3,607)	(1,583)	(7,535)
Gain on sale of other assets	0	2,576	0	2,576
Income (loss) from equity method investment	52	688	(91)	671
Interest expense and other income, net	(197)	33	(116)	(169)
Loss before income taxes	(1,545)	(310)	(1,790)	(4,457)
Income tax provision	194	1,670	284	1,970
Net loss	(1,739)	(1,980)	(2,074)	(6,427)
Add: net loss attributable to noncontrolling interest	319	481	599	914
Net loss attributable to Amtech Systems, Inc.	$ (1,420)	$ (1,499)	$ (1,475)	$ (5,513)
Loss Per Share:
Basic loss per share attributable to Amtech shareholders (USD per share)	$ (0.11)	$ (0.11)	$ (0.11)	$ (0.42)
Weighted average shares outstanding (in shares)	13,188	13,169	13,184	13,161
Diluted loss per share attributable to Amtech shareholders (dollars per share)	$ (0.11)	$ (0.11)	$ (0.11)	$ (0.42)
Weighted average shares outstanding (in shares)	13,188	13,169	13,184	13,161