Condensed Consolidated Statements of Operations and Comprehensive Income (Loss) (unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020
Income Statement [Abstract]
Revenue	$ 38,406	$ 23,850	$ 71,832	$ 49,332
Cost of revenue	23,772	17,423	44,626	35,431
Gross profit	14,634	6,427	27,206	13,901
Operating expense:
Selling, general, and administrative	6,062	7,139	11,860	13,026
Research and development	3,771	4,584	8,067	9,226
Loss (gain) on sale of assets	218	(315)	189	(1,917)
Total operating expense	10,051	11,408	20,116	20,335
Operating income (loss)	4,583	(4,981)	7,090	(6,434)
Other (expense) income:
Interest (expense) income, net	(49)	1	(98)	(14)
Foreign exchange (loss) gain	(68)	(156)	169	(9)
Total other (expense) income	(117)	(155)	71	(23)
Income (loss) before income tax (expense) benefit	4,466	(5,136)	7,161	(6,457)
Income tax (expense) benefit	(82)	55	(208)	41
Net income (loss)	4,384	(5,081)	6,953	(6,416)
Foreign exchange translation adjustment	(11)	29	(21)	(7)
Comprehensive income (loss)	$ 4,373	$ (5,052)	$ 6,932	$ (6,423)
Per share data:
Net income (loss) per basic share (in dollars per share)	$ 0.13	$ (0.18)	$ 0.22	$ (0.22)
Weighted-average number of basic shares outstanding (in shares)	32,968	29,033	31,219	28,931
Net income (loss) per diluted share (in dollars per share)	$ 0.13	$ (0.18)	$ 0.21	$ (0.22)
Weighted-average number of diluted shares outstanding (in shares)	34,451	29,033	32,492	28,931