Condensed Statements of Cash Flows (Unaudited) - USD ($)	9 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Cash flows from operating activities
Net income	$ 2,587,767	$ 5,342,494
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	1,205,769	1,068,297
Impairment of long-lived assets	643,604	0
Deferred taxes		2,185,534
(Gain) loss on disposal of assets	(5,100)	1,135
Stock-based compensation	1,774,330	843,658
Changes in operating assets and liabilities:
Accounts receivable, net	(53,619)	(2,716,263)
Inventories	(965,458)	(923,530)
Prepaid expenses and other	324,206	(399,662)
Accounts payable and accrued expenses	(2,989,849)	1,526,993
Net cash provided by operating activities	2,521,650	6,928,656
Cash flows from investing activities
Purchases of property, plant and equipment and intangible assets	(1,631,127)	(982,245)
Proceeds from sale of property, plant and equipment	5,100
Purchases of investments	(13,279,075)	(5,508,075)
Proceeds from maturities of investments	6,619,000	5,761,000
Net cash used in investing activities	(8,286,102)	(729,320)
Cash flows from financing activities
Proceeds from issuance of common stock under employee stock purchase plan	334,692	254,426
Proceeds from issuance of common stock upon exercise of stock options	28,718	473,651
Tax withholding related to exercise of stock options and restricted stock vestings	(462,120)	(77,291)
Repurchase of common stock	(2,403,062)	(333,761)
Net cash (used in) provided by financing activities	(2,501,772)	317,025
(Decrease) increase in cash and cash equivalents	(8,266,224)	6,516,361
Cash and cash equivalents, beginning of period	28,014,321	18,071,210
Cash and cash equivalents, end of period	19,748,097	24,587,571
Supplemental disclosures for cash flow information
Cash paid during the year for income taxes	893,483	338,616
Non-cash financing activities
Cashless exercise of stock options	$ 34,268	$ 541,016