Note 7 - Results of Operations by Quarter (Unaudited) - Summary of Operations by Quarter (Details) - USD ($)	3 Months Ended										12 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018		Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017		Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Revenue from Contract with Customer, Including Assessed Tax	$ 10,428,000	$ 10,712,000	$ 14,518,000	$ 12,997,000		$ 10,252,000	$ 9,338,000	$ 11,007,000	$ 10,106,000		$ 48,655,000	$ 40,703,000	$ 41,384,000
Costs and expenses	12,949,000	13,383,000	13,394,000	27,153,000	[1]	13,697,000	13,711,000	13,716,000	13,639,000
Loss from operations	(2,521,000)	(2,671,000)	1,124,000	(14,156,000)		(3,445,000)	(4,373,000)	(2,709,000)	(3,533,000)
Other income, net	1,311,000	909,000	1,105,000	1,138,000		1,334,000	4,041,000	1,027,000	879,000	[1]
Unrealized (losses) gains on investments	(28,640,000)	8,497,000	3,214,000	(786,000)							(17,715,000)
Loss before taxes	(29,850,000)	6,735,000	5,443,000	(13,804,000)		(2,111,000)	(332,000)	(1,682,000)	(7,214,000)		(31,476,000)	(11,339,000)	(8,068,000)
Benefit from income taxes	8,317,000	(1,717,000)	(1,620,000)	1,280,000		16,850,000	100,000	710,000	1,880,000		6,260,000	19,540,000	7,150,000
Net (loss) income	$ (21,533,000)	$ 5,018,000	$ 3,823,000	$ (12,524,000)		$ 14,739,000	$ (232,000)	$ (972,000)	$ (5,334,000)		$ (25,216,000)	$ 8,201,000	$ (918,000)
Basic and diluted net (loss) income per share (in dollars per share)	$ (15.60)	$ 3.63	$ 2.77	$ (9.06)		$ 10.67	$ (0.17)	$ (0.70)	$ (3.86)		$ (18.26)	$ 5.94	$ (0.66)
Goodwill impairment	$ 13,400,000										$ 13,400,000
Other-than-temporary impairment losses on investments									$ (4,560,000)			$ (4,560,000)

[1] Included goodwill impairment of $13.4 million