Financial Instruments and Fair Value Measurements - Fair Value Measurements (Details) - USD ($) $ in Thousands	Dec. 11, 2020	Mar. 31, 2021	Dec. 31, 2020
ISP Fund LP
Debt
Lock-up period	36 months
Recurring basis
Assets
Total assets measured at estimated fair value		$ 746,051	$ 627,254
Recurring basis | Money market funds
Assets
Total assets measured at estimated fair value		248,932	204,808
Recurring basis | Money market funds | ISP Fund LP
Assets
Total assets measured at estimated fair value		174,200	284,800
Recurring basis | Equity investments and Money market funds | ISP Fund LP
Assets
Total assets measured at estimated fair value		304,696	299,288
Recurring basis | Equity investment | ISP Fund LP
Assets
Total assets measured at estimated fair value		130,500	14,500
Recurring basis | Quoted Price in Active Markets for Identical Assets, Level 1
Assets
Total assets measured at estimated fair value		664,641	576,176
Recurring basis | Quoted Price in Active Markets for Identical Assets, Level 1 | Money market funds
Assets
Total assets measured at estimated fair value		248,932	204,808
Recurring basis | Quoted Price in Active Markets for Identical Assets, Level 1 | Equity investments and Money market funds | ISP Fund LP
Assets
Total assets measured at estimated fair value		304,696	299,288
Recurring basis | Significant Other Observable Inputs, Level 2
Assets
Total assets measured at estimated fair value		80,746	49,931
Recurring basis | Significant Other Observable Inputs, Level 2 | Money market funds
Assets
Total assets measured at estimated fair value		0	0
Recurring basis | Significant Other Observable Inputs, Level 2 | Equity investments and Money market funds | ISP Fund LP
Assets
Total assets measured at estimated fair value		0	0
Recurring basis | Significant Unobservable Inputs, Level 3
Assets
Total assets measured at estimated fair value		664	1,147
Recurring basis | Significant Unobservable Inputs, Level 3 | Money market funds
Assets
Total assets measured at estimated fair value		0	0
Recurring basis | Significant Unobservable Inputs, Level 3 | Equity investments and Money market funds | ISP Fund LP
Assets
Total assets measured at estimated fair value		0	0
Nonrecurring basis | Debt
Debt
2023 Notes		242,336	239,779
2025 Notes		203,513	206,135
Total fair value of debt		445,849	445,914
Nonrecurring basis | Quoted Price in Active Markets for Identical Assets, Level 1 | Debt
Debt
2023 Notes		0	0
2025 Notes		0	0
Total fair value of debt		0	0
Nonrecurring basis | Significant Other Observable Inputs, Level 2 | Debt
Debt
2023 Notes		242,336	239,779
2025 Notes		203,513	206,135
Total fair value of debt		445,849	445,914
Nonrecurring basis | Significant Unobservable Inputs, Level 3 | Debt
Debt
2023 Notes		0	0
2025 Notes		0	0
Total fair value of debt		0	0
Armata | Recurring basis | Equity investment | Common stock
Assets
Total assets measured at estimated fair value		71,053	25,958
Armata | Recurring basis | Equity investment | Warrants
Assets
Total assets measured at estimated fair value		54,166	18,049
Armata | Recurring basis | Quoted Price in Active Markets for Identical Assets, Level 1 | Equity investment | Common stock
Assets
Total assets measured at estimated fair value		71,053	25,958
Armata | Recurring basis | Quoted Price in Active Markets for Identical Assets, Level 1 | Equity investment | Warrants
Assets
Total assets measured at estimated fair value		0	0
Armata | Recurring basis | Significant Other Observable Inputs, Level 2 | Equity investment | Common stock
Assets
Total assets measured at estimated fair value		0	0
Armata | Recurring basis | Significant Other Observable Inputs, Level 2 | Equity investment | Warrants
Assets
Total assets measured at estimated fair value		54,166	18,049
Armata | Recurring basis | Significant Unobservable Inputs, Level 3 | Equity investment | Common stock
Assets
Total assets measured at estimated fair value		0	0
Armata | Recurring basis | Significant Unobservable Inputs, Level 3 | Equity investment | Warrants
Assets
Total assets measured at estimated fair value		0	0
Entasis | Recurring basis | Equity investment | Common stock
Assets
Total assets measured at estimated fair value		39,960	46,122
Entasis | Recurring basis | Equity investment | Warrants
Assets
Total assets measured at estimated fair value		26,580	31,882
Entasis | Recurring basis | Quoted Price in Active Markets for Identical Assets, Level 1 | Equity investment | Common stock
Assets
Total assets measured at estimated fair value		39,960	46,122
Entasis | Recurring basis | Quoted Price in Active Markets for Identical Assets, Level 1 | Equity investment | Warrants
Assets
Total assets measured at estimated fair value		0	0
Entasis | Recurring basis | Significant Other Observable Inputs, Level 2 | Equity investment | Common stock
Assets
Total assets measured at estimated fair value		0	0
Entasis | Recurring basis | Significant Other Observable Inputs, Level 2 | Equity investment | Warrants
Assets
Total assets measured at estimated fair value		26,580	31,882
Entasis | Recurring basis | Significant Unobservable Inputs, Level 3 | Equity investment | Common stock
Assets
Total assets measured at estimated fair value		0	0
Entasis | Recurring basis | Significant Unobservable Inputs, Level 3 | Equity investment | Warrants
Assets
Total assets measured at estimated fair value		0	0
InCarda | Recurring basis | Equity investment | Warrants
Assets
Total assets measured at estimated fair value		664	1,147
InCarda | Recurring basis | Quoted Price in Active Markets for Identical Assets, Level 1 | Equity investment | Warrants
Assets
Total assets measured at estimated fair value		0	0
InCarda | Recurring basis | Significant Other Observable Inputs, Level 2 | Equity investment | Warrants
Assets
Total assets measured at estimated fair value		0	0
InCarda | Recurring basis | Significant Unobservable Inputs, Level 3 | Equity investment | Warrants
Assets
Total assets measured at estimated fair value		$ 664	$ 1,147