Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Income Statement [Abstract]
Revenues, net of returns and allowances	$ 41,200	$ 47,760	$ 147,594	$ 109,839
Cost of sales	26,601	32,258	100,933	77,499
Gross profit	14,599	15,502	46,661	32,340
Selling, general and administrative	9,541	10,108	29,599	25,366
Research, development and engineering	2,122	1,423	6,295	4,586
Operating income	2,936	3,971	10,767	2,388
Gain on sale of other assets	2,883	0	2,883	0
Income (loss) from equity method investment	232	(110)	234	(200)
Interest expense and other income, net	310	(34)	224	(151)
Income before income taxes	6,361	3,827	14,108	2,037
Income tax provision (benefit)	1,390	986	(150)	1,270
Net income	4,971	2,841	14,258	767
Add: net loss attributable to noncontrolling interest	0	446	0	1,045
Net income attributable to Amtech Systems, Inc.	$ 4,971	$ 3,287	$ 14,258	$ 1,812
Income Per Share:
Basic income per share attributable to Amtech shareholders (USD per share)	$ 0.33	$ 0.25	$ 0.96	$ 0.14
Weighted average shares outstanding (in shares)	14,925	13,242	14,867	13,203
Diluted income per share attributable to Amtech shareholders (USD per share)	$ 0.33	$ 0.25	$ 0.94	$ 0.14
Weighted average shares outstanding (in shares)	15,091	13,398	15,181	13,288