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Significant Transactions (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
Significant Transactions (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Schedule of Equity Method Investments [Line Items]
Investment in Zentera Therapeutics	$ 39,326		$ 39,326		$ 0
Gain on deconsolidation of Zentera, net of tax	51,582	$ 0	51,582	$ 0
Zentera
Schedule of Equity Method Investments [Line Items]
Deferred tax liability, deconsolidation of Zentera	1,700		$ 1,700
Gain on deconsolidation of Zentera, net of tax	51,600
Contra-research and development expense	$ 2,900