Quarterly Financial Data (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended																12 Months Ended
	Sep. 30, 2019		Jun. 30, 2019		Mar. 31, 2019		Dec. 31, 2018		Sep. 30, 2018	[1]	Jun. 30, 2018	[1]	Mar. 31, 2018	[1]	Dec. 31, 2017	[1]	Sep. 30, 2019	Sep. 30, 2018	[1]	Sep. 30, 2017	[1]
Quarterly Financial Information Disclosure [Abstract]
Total revenues	$ 64,960		$ 61,166		$ 65,764		$ 62,313		$ 65,118		$ 62,272		$ 54,548		$ 44,955		$ 254,203	$ 226,893		$ 181,340
Gross profit	30,595		28,328		30,329		29,783		30,613		29,648		26,834		21,959		119,035	109,054		87,233
Net (loss) income	$ 2,286	[2]	$ 1,648	[2]	$ 1,342	[2]	$ 4,682	[2]	$ 3,340	[2]	$ 2,904	[2]	$ (126)	[2]	$ (4,487)	[2]	$ 9,958	$ 1,631		$ 9,403
Net (loss) income per common share, basic (USD per share)	$ 0.08		$ 0.06		$ 0.05		$ 0.17		$ 0.12		$ 0.11		$ 0.00		$ (0.17)		$ 0.36	$ 0.06		$ 0.36
Net (loss) income per common share, diluted (USD per share)	$ 0.08		$ 0.06		$ 0.05		$ 0.17		$ 0.12		$ 0.10		$ 0.00		$ (0.17)		$ 0.35	$ 0.06		$ 0.35

[1] Prior period information has been restated for the adoption of ASU No. 2014-09, “Revenue from Contracts with Customers (Topic 606)”, which we adopted on October 1, 2018.

[2] During fiscal 2019, we recorded a discrete tax benefit of $0.1 million in the first quarter of fiscal 2019 resulting from reversal of income tax reserves due to the expiration of the statutes of limitation as well as excess tax benefits recognized on stock compensation. In the second quarter of fiscal 2019 we recorded a discrete tax benefit of $0.2 million related to the recording of federal and state net operating losses as well as the reversal of income tax reserves due to the expiration of the statutes of limitation. In the third quarter of fiscal 2019, we recorded a discrete tax benefit of $0.3 million from reversal of income tax reserves due to the expiration of the statutes of limitation as well as adjustments from the filing of the federal and foreign income tax returns.During fiscal 2018, we recorded discrete tax expense of $2.8 million in the first quarter of fiscal 2018, $0.2 million in the second quarter of fiscal 2018 and $0.1 million in the third quarter of fiscal 2018 resulting from new U.S. tax legislation that was enacted during the first quarter of fiscal 2018 and the adoption of ASU 2016-09 relating to the accounting for the tax effects of stock compensation. In the fourth quarter of fiscal 2018, we recorded a net tax benefit of $1.5 million for the release of a valuation allowance against U.S. federal capital loss carryforward due to expected capital gains tax in fiscal 2019 resulting from the sale of our corporate headquarters building in October 2018 (see Note 5 to the consolidated financial statements).