CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenue from Contract with Customer, Excluding Assessed Tax	$ 75.7	$ 10.6	$ 120.7	$ 49.3
Revenue	75.7	10.6	120.7	49.3
Cost of sales	31.9	14.9	57.3	59.1
Gross profit (loss)	43.8	(4.3)	63.4	(9.8)
Advanced technology license and decommissioning costs	0.7	5.1	1.6	11.7
Selling, general and administrative	10.4	7.7	18.9	15.8
Amortization of intangible assets	1.7	1.2	3.1	2.3
Special charges for workforce reductions and advisory costs	0.0	(2.9)	(0.1)	(3.0)
Other (income)	0.0	(0.1)	0.0	(0.5)
Operating income (loss)	31.0	(15.3)	39.9	(36.1)
Nonoperating components of net periodic benefit expense (income)	(2.2)	0.0	(4.4)	(0.1)
Interest expense	0.0	1.0	0.1	2.0
Investment income	0.0	(0.7)	(0.4)	(1.4)
Income (loss) before income taxes	33.2	(15.6)	44.6	(36.6)
Provision (benefit) for income taxes	(0.5)	0.0	(0.4)	(0.1)
Net income (loss)	33.7	(15.6)	45.0	(36.5)
Preferred stock dividends, undeclared and cumulative	2.0	2.0	4.0	4.0
Net income (loss) allocable to common stockholders	$ 31.7	$ (17.6)	$ 41.0	$ (40.5)
Net income (loss) per common share - basic	$ 3.28	$ (1.84)	$ 4.25	$ (4.24)
Net income (loss) per common share - diluted	$ 3.19	$ (1.84)	$ 4.15	$ (4.24)
Weighted-average number of shares outstanding:
Average number of shares outstanding, basic	9,675	9,565	9,647	9,549
Average number of shares outstanding, diluted	9,927	9,565	9,882	9,549
Separative Work Units [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 58.6	$ 0.0	$ 89.3	$ 12.4
Uranium [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	4.8	2.6	4.8	25.3
Product [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	63.4	2.6	94.1	37.7
Cost of sales	18.9	7.7	32.2	46.0
Service [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	12.3	8.0	26.6	11.6
Cost of sales	$ 13.0	$ 7.2	$ 25.1	$ 13.1