Financial Instruments and Fair Value Measurements - Fair Value Measurements (Details) - USD ($) $ in Thousands	Dec. 11, 2020	Jun. 30, 2021	Dec. 31, 2020
ISP Fund LP
Debt
Lock-up period	36 months
Recurring basis
Assets
Total assets measured at estimated fair value		$ 454,335	$ 627,254
Recurring basis | Money market funds
Assets
Total assets measured at estimated fair value		2,843	204,808
Recurring basis | Equity investments and money market funds | ISP Fund LP
Assets
Total assets measured at estimated fair value		218,978	299,288
Recurring basis | Quoted Price in Active Markets for Identical Assets, Level 1
Assets
Total assets measured at estimated fair value		357,391	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		2,843	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		218,978	299,288
Recurring basis | Significant Other Observable Inputs, Level 2
Assets
Total assets measured at estimated fair value		96,534	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		410	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		246,298	239,779
2025 Notes		210,185	206,135
Total fair value of debt		456,483	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		246,298	239,779
2025 Notes		210,185	206,135
Total fair value of debt		456,483	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		59,013	25,958
Armata | Recurring basis | Equity investment | Warrants
Assets
Total assets measured at estimated fair value		41,874	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		59,013	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		41,874	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		76,557	46,122
Entasis | Recurring basis | Equity investment | Warrants
Assets
Total assets measured at estimated fair value		54,660	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		76,557	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		54,660	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		410	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		$ 410	$ 1,147