Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Operating Activities:
Net income (loss)	$ 2,784,992	$ (3,745,042)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	824,889	483,087
Provision for doubtful accounts	(23,407)	150,000
Warranty provision	85,078	6,093
Inventory obsolescence	142,288	171,535
Share-based compensation	735,003	584,873
Deferred income taxes	570,000	2,374,000
Gain on disposition of asset		252
Loss on impairment of patents		11,133
Changes in operating assets and liabilities:
Accounts receivable	(854,676)	3,149,579
Inventories	756,732	(1,648,484)
Prepaid expenses and other	1,358,690	(2,075,323)
Other assets	116,973	(60,615)
Accounts payable	(2,211,695)	192,638
Payroll and related	(67,692)	127,623
Warranty settlements	(34,065)	(11,395)
Accrued and other liabilities	5,671,921	1,541,865
Net cash provided by operating activities	9,855,031	1,251,819
Investing Activities:
Purchases of marketable securities	(4,495,228)	(4,920,547)
Proceeds from maturities of marketable securities	4,228,068	5,190,821
Capital expenditures	(343,126)	(625,845)
Purchase of Genasys, net of cash and restricted cash acquired		(2,431,795)
Net cash used in investing activities	(610,286)	(2,787,366)
Financing Activities:
Proceeds from exercise of stock options	703,313	2,434,888
Repurchase of common stock	(2,171,022)	(725,445)
Proceeds from the issuance of unsecured promissory notes		62,656
Payments on promissory notes	(17,044)	(1,175,205)
Net cash (used in) provided by financing activities	(1,484,753)	596,894
Effect of foreign exchange rate on cash	(49,148)	(59,160)
Net increase (decrease) in cash, cash equivalents, and restricted cash	7,710,844	(997,813)
Cash, cash equivalents and restricted cash, beginning of period	11,806,074	12,803,887
Cash, cash equivalents and restricted cash, end of period	19,516,918	11,806,074
Total cash, cash equivalents and restricted cash shown in the consolidated statement of cash flows	19,516,918	12,803,887
Supplemental disclosures of cash flow information:
Interest paid	2,860	18,015
Noncash investing and financing activities:
Change in unrealized gain (loss) on marketable securities	20,307	(7,676)
Business combinations accounted for as a purchase:
Fair value of assets acquired		5,520,504
Cash paid or payable		(3,011,439)
Liabilities assumed		$ 2,509,065