Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Current assets:
Cash and cash equivalents	$ 33,700	$ 9,594
Accounts receivable (net of allowance of $168 and $156 at June 30, 2025 and December 31, 2024, respectively)	8,981	10,662
Inventories	466	1,231
Prepaids and other current assets	4,606	2,856
Total current assets	47,753	24,343
Property, plant and equipment, at cost	35,967	301,417
Less accumulated depreciation	(25,910)	(288,784)
Property, plant and equipment, net	10,057	12,633
Operating lease right-of-use assets	16,210	17,434
Deferred income taxes, net	399	5,609
Other assets	1,816	1,824
Total assets	76,235	61,843
Current liabilities:
Accounts payable	3,884	4,808
Accrued compensation and benefits	3,907	4,234
Other accrued expense	4,087	7,264
Contract liabilities	8,852	8,689
Total current liabilities	20,730	24,995
Long-term pension liabilities		11,764
Long-term operating lease liabilities	16,155	17,379
Other post-employment benefits	854	880
Other liabilities	12	12
Total liabilities	37,751	55,030
Commitments and contingencies (Note 10)
Shareholders' equity:
Preferred stock, $0.01 par value; Authorized 2,000,000 shares; none issued
Treasury stock, Series A, at cost; 478,465 shares held at June 30, 2025 and December 31, 2024	(13,443)	(13,443)
Additional paid-in capital	494,563	494,563
Accumulated other comprehensive loss	355	(36,523)
Accumulated deficit	(443,049)	(437,842)
Total shareholders’ equity	38,484	6,813
Total liabilities and shareholders’ equity	76,235	61,843
Series A [Member]
Shareholders' equity:
Common stock, $0.01 par value; Authorized 31,250,000 shares	52	52
Series B [Member]
Shareholders' equity:
Common stock, $0.01 par value; Authorized 31,250,000 shares	$ 6	$ 6