Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Income Statement [Abstract]
Revenues, net of returns and allowances	$ 47,760	$ 33,342	$ 109,839	$ 77,899
Cost of sales	32,258	23,711	77,499	56,312
Gross profit	15,502	9,631	32,340	21,587
Selling, general and administrative	10,108	8,665	25,366	23,709
Research, development and engineering	1,423	1,568	4,586	6,015
Operating income (loss)	3,971	(602)	2,388	(8,137)
Gain on sale of other assets	0	0	0	2,576
(Loss) income from equity method investment	(110)	(444)	(200)	227
Interest expense and other income, net	(34)	(265)	(151)	(434)
Income (loss) before income taxes	3,827	(1,311)	2,037	(5,768)
Income tax provision	986	70	1,270	2,040
Net income (loss)	2,841	(1,381)	767	(7,808)
Add: net loss attributable to noncontrolling interest	446	172	1,045	1,086
Net income (loss) attributable to Amtech Systems, Inc.	$ 3,287	$ (1,209)	$ 1,812	$ (6,722)
Income (Loss) Per Share:
Basic income (loss) per share attributable to Amtech shareholders (USD per share)	$ 0.25	$ (0.09)	$ 0.14	$ (0.51)
Weighted average shares outstanding (in shares)	13,242	13,173	13,203	13,165
Diluted income (loss) per share attributable to Amtech shareholders (USD per share)	$ 0.25	$ (0.09)	$ 0.14	$ (0.51)
Weighted average shares outstanding (in shares)	13,398	13,173	13,288	13,165