CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Cash flows provided by (used in) operating activities:
Net income	$ 15,306	$ 3,257
Adjustments to reconcile net income to net cash and cash equivalents provided by operating activities:
Depreciation of property and equipment	42	68
Reduction in carrying value of right of use assets	231	353
Stock-based compensation	1,707	1,932
Net (gains) losses on investment in marketable securities	(7,206)	3,644
Net (gain) loss on derivative instruments	(2,044)	2,728
Deferred income taxes	0	(124)
Foreign currency remeasurement gains (losses)	(2)	139
Shares issued to an employee in lieu of cash compensation	490	84
Other non cash	(55)	5
Changes in operating assets and liabilities:
Accounts and other receivables	(1,109)	47
Prepaid expenses and other current assets	2,467	3,882
Long-term deposits	(1,980)	5,072
Other assets	231	997
Accounts payable	(33)	74
Accrued compensation	(723)	570
Other current liabilities	3,845	(872)
Deferred revenue	(2,379)	(2,542)
Other long-term liabilities	(34)	(675)
Net cash and cash equivalents provided by operating activities	8,754	18,639
Cash flows provided by (used in) investing activities:
Purchases of marketable securities and other investments	(99,766)	(71,959)
Proceeds from sale or maturities of marketable securities and other investments	72,442	64,876
Proceeds from sale of derivative instruments	9,487	9,272
Payments for settlement of derivative instruments	(4,869)	(8,903)
Purchases of property and equipment	0	(8)
Net cash and cash equivalents used in investing activities	(22,706)	(6,722)
Cash flows provided by (used in) financing activities:
Dividend payments to stockholders	(5,415)	0
Payment for purchases of treasury stock	(2,852)	(5,976)
Proceeds from issuance of common stock under employee stock purchase plan	6	34
Proceeds from stock options exercises	160	0
Shares withheld to cover payroll taxes	(947)	(80)
Other financing activities	0	5
Net cash and cash equivalents used in financing activities	(9,048)	(6,017)
Net increase (decrease) in cash and cash equivalents	(23,000)	5,900
Cash and cash equivalents:
Beginning of period	48,820	51,490
End of period	25,820	57,390
Supplemental disclosure of cash flow information:
Cash paid for income taxes	636	647
Supplemental disclosure of non-cash investing, and financing activities:
Dividends declared but not yet paid	1,003	0
Leased assets obtained in exchange for new operating lease liabilities	$ 0	$ 120