Income Taxes: (Details) - USD ($)	12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Current provision (benefit):
Federal	$ (375,936)	$ 614,729	$ 432,211
State	(10,146)	363	(2,731)
Total current provision (benefit)	(386,082)	615,092	429,480
Deferred provision (benefit):
Federal	2,598,050	(857,049)	(255,154)
State	91,510	(41,665)	(54,484)
Total deferred provision (benefit)	2,689,560	(898,714)	(309,638)
Total current and deferred provision (benefit)	$ 2,303,478	$ (283,622)	$ 119,842
Reconciliation of the statutory federal rate to the Company's effective income tax rate
U.S. Federal statutory tax rate (as a percent)	34.00%	34.00%	34.00%
State income taxes, net of federal benefit (as a percent)	0.00%	29.60%	(1.30%)
Permanent items	(2.50%)	123.90%	(2.90%)
Research and development tax credits (as a percent)	17.40%	190.40%	(27.40%)
Valuation allowance (as a percent)	(111.00%)	3.90%	(0.80%)
Change in unrecognized tax benefits (as a percent)	(2.60%)	(41.50%)	4.40%
Effective income tax rate (as a percent)	(64.70%)	340.30%	6.00%