Equity and Long-term Investments and Fair Value Measurements - Convertible Promissory Note in Gate Neuroscience (Details) - USD ($) $ in Thousands			3 Months Ended		9 Months Ended
	Feb. 02, 2023	Nov. 24, 2021	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Equity Investment
Additional cash investment					$ 1,218	$ 13,725
Gate Neuroscience [Member]
Equity Investment
Number Of Common Stock Issued Description		The number of common stock shares to be issued in a qualified event shall be equal to the amount due on the conversion date divided by the lesser of a capped conversion price (the “Capped Conversion Price”) and the qualified event price (the “Qualified Event Price”). The Capped Conversion Price is calculated as $50.0 million divided by the number of shares of common stock outstanding at such time on a fully diluted basis. The Qualified Event Price is the price per share determined by the qualified event. A qualified financing is a sale or series of sales of preferred stock where (i) at least 50 percent of counterparties are not existing shareholders, (ii) net proceeds to Gate are at least $35.0 million, and (iii) the stated or implied equity valuation of Gate is at least $80.0 million.
Additional cash investment	$ 5,000
Equity and long-term investments at fair value			$ 22,300		22,300		$ 15,700
Unrealized gain			$ 100	$ 200	$ 800	$ 300
Convertible Promissory Note Purchase Agreement | Gate Neuroscience [Member]
Equity Investment
Convertible notes Face Value		$ 15,000
Debt Instrument, Interest Rate, Effective Percentage		8.00%
Note Amendment Agreement | Gate Neuroscience [Member]
Equity Investment
Convertible notes Face Value	$ 21,500