CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Revenue from Contract with Customer, Excluding Assessed Tax	$ 33.6	$ 104.7	$ 154.3	$ 154.0
Revenue	33.6	104.7	154.3	154.0
Cost of sales	34.4	69.2	91.7	128.3
Gross profit (loss)	(0.8)	35.5	62.6	25.7
Advanced technology license and decommissioning costs	0.2	1.3	1.8	13.0
Selling, general and administrative	6.7	8.7	25.6	24.5
Amortization of intangible assets	1.2	1.8	4.3	4.1
Special charges for workforce reductions and advisory costs	0.6	0.8	0.5	(2.2)
Gain on Sales of Assets	0.0	(0.2)	0.0	(0.7)
Operating income (loss)	(9.5)	23.1	30.4	(13.0)
Nonoperating components of net periodic benefit expense (income)	(2.2)	(0.1)	(6.6)	(0.2)
Interest expense	0.0	0.9	0.1	2.9
Investment income	(0.1)	(0.5)	(0.5)	(1.9)
Income (loss) before income taxes	(7.2)	22.8	37.4	(13.8)
Provision (benefit) for income taxes	(0.2)	0.0	(0.6)	(0.1)
Net income (loss)	(7.0)	22.8	38.0	(13.7)
Preferred stock dividends, undeclared and cumulative	1.9	1.9	5.9	5.9
Net income (loss) allocable to common stockholders	$ (8.9)	$ 20.9	$ 32.1	$ (19.6)
Net income (loss) per common share - basic	$ (0.83)	$ 2.18	$ 3.21	$ (2.05)
Net income (loss) per common share - diluted	$ (0.83)	$ 2.17	$ 3.12	$ (2.05)
Weighted-average number of shares outstanding:
Average number of shares outstanding, basic	10,723	9,582	10,008	9,560
Average number of shares outstanding, diluted	10,723	9,626	10,282	9,560
Separative Work Units [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 0.1	$ 75.0	$ 89.4	$ 87.4
Uranium [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	18.6	12.8	23.4	38.1
Product [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	18.7	87.8	112.8	125.5
Cost of sales	19.6	54.4	51.8	100.4
Service [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	14.9	16.9	41.5	28.5
Cost of sales	$ 14.8	$ 14.8	$ 39.9	$ 27.9