Fair Value Measures (Assets and Liabilities Measured at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Thousands | Dec. 31, 2021 | Dec. 31, 2020 |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets, Fair Value Disclosure | $ 175,186 | $ 378,023 |
Liabilities, Fair Value Disclosure | 3,890 | 16,431 |
Fair Value, Inputs, Level 1 [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets, Fair Value Disclosure | 25,479 | 139,318 |
Liabilities, Fair Value Disclosure | 0 | 0 |
Fair Value, Inputs, Level 2 [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets, Fair Value Disclosure | 149,707 | 238,705 |
Liabilities, Fair Value Disclosure | 3,890 | 16,431 |
Fair Value, Inputs, Level 3 [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets, Fair Value Disclosure | 0 | 0 |
Liabilities, Fair Value Disclosure | 0 | 0 |
Money Market Funds [Member] | Cash Equivalents [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets, Fair Value Disclosure | 2,677 | 119,378 |
Money Market Funds [Member] | Short-term Investments [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets, Fair Value Disclosure | 73 | |
Money Market Funds [Member] | Other Noncurrent Assets [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets, Fair Value Disclosure | 2,219 | 4,059 |
Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member] | Cash Equivalents [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets, Fair Value Disclosure | 2,677 | 119,378 |
Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member] | Short-term Investments [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets, Fair Value Disclosure | 73 | |
Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member] | Other Noncurrent Assets [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets, Fair Value Disclosure | 2,219 | 4,059 |
Money Market Funds [Member] | Fair Value, Inputs, Level 2 [Member] | Cash Equivalents [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets, Fair Value Disclosure | 0 | 0 |
Money Market Funds [Member] | Fair Value, Inputs, Level 2 [Member] | Short-term Investments [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets, Fair Value Disclosure | 0 | |
Money Market Funds [Member] | Fair Value, Inputs, Level 2 [Member] | Other Noncurrent Assets [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets, Fair Value Disclosure | 0 | 0 |
Money Market Funds [Member] | Fair Value, Inputs, Level 3 [Member] | Cash Equivalents [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets, Fair Value Disclosure | 0 | 0 |
Money Market Funds [Member] | Fair Value, Inputs, Level 3 [Member] | Short-term Investments [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets, Fair Value Disclosure | 0 | |
Money Market Funds [Member] | Fair Value, Inputs, Level 3 [Member] | Other Noncurrent Assets [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets, Fair Value Disclosure | 0 | 0 |
US Treasury Securities [Member] | Cash Equivalents [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets, Fair Value Disclosure | | 234,982 |
US Treasury Securities [Member] | Available-for-sale Securities [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets, Fair Value Disclosure | 130,168 | |
US Treasury Securities [Member] | Fair Value, Inputs, Level 1 [Member] | Cash Equivalents [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets, Fair Value Disclosure | | 0 |
US Treasury Securities [Member] | Fair Value, Inputs, Level 1 [Member] | Available-for-sale Securities [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets, Fair Value Disclosure | 0 | |
US Treasury Securities [Member] | Fair Value, Inputs, Level 2 [Member] | Cash Equivalents [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets, Fair Value Disclosure | | 234,982 |
US Treasury Securities [Member] | Fair Value, Inputs, Level 2 [Member] | Available-for-sale Securities [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets, Fair Value Disclosure | 130,168 | |
US Treasury Securities [Member] | Fair Value, Inputs, Level 3 [Member] | Cash Equivalents [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets, Fair Value Disclosure | | 0 |
US Treasury Securities [Member] | Fair Value, Inputs, Level 3 [Member] | Available-for-sale Securities [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets, Fair Value Disclosure | 0 | |
Derivative Financial Instruments, Assets [Member] | Other Current Assets [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets, Fair Value Disclosure | 9,397 | 2,597 |
Derivative Financial Instruments, Assets [Member] | Other Noncurrent Assets [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets, Fair Value Disclosure | 10,142 | 1,126 |
Derivative Financial Instruments, Assets [Member] | Fair Value, Inputs, Level 1 [Member] | Other Current Assets [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets, Fair Value Disclosure | 0 | 0 |
Derivative Financial Instruments, Assets [Member] | Fair Value, Inputs, Level 1 [Member] | Other Noncurrent Assets [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets, Fair Value Disclosure | 0 | 0 |
Derivative Financial Instruments, Assets [Member] | Fair Value, Inputs, Level 2 [Member] | Other Current Assets [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets, Fair Value Disclosure | 9,397 | 2,597 |
Derivative Financial Instruments, Assets [Member] | Fair Value, Inputs, Level 2 [Member] | Other Noncurrent Assets [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets, Fair Value Disclosure | 10,142 | 1,126 |
Derivative Financial Instruments, Assets [Member] | Fair Value, Inputs, Level 3 [Member] | Other Current Assets [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets, Fair Value Disclosure | 0 | 0 |
Derivative Financial Instruments, Assets [Member] | Fair Value, Inputs, Level 3 [Member] | Other Noncurrent Assets [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets, Fair Value Disclosure | 0 | 0 |
Derivative Financial Instruments, Liabilities [Member] | Accrued Liabilities [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Liabilities, Fair Value Disclosure | 3,572 | 9,841 |
Derivative Financial Instruments, Liabilities [Member] | Other Noncurrent Liabilities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Liabilities, Fair Value Disclosure | 318 | 6,590 |
Derivative Financial Instruments, Liabilities [Member] | Fair Value, Inputs, Level 1 [Member] | Accrued Liabilities [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Liabilities, Fair Value Disclosure | 0 | 0 |
Derivative Financial Instruments, Liabilities [Member] | Fair Value, Inputs, Level 1 [Member] | Other Noncurrent Liabilities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Liabilities, Fair Value Disclosure | 0 | 0 |
Derivative Financial Instruments, Liabilities [Member] | Fair Value, Inputs, Level 2 [Member] | Accrued Liabilities [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Liabilities, Fair Value Disclosure | 3,572 | 9,841 |
Derivative Financial Instruments, Liabilities [Member] | Fair Value, Inputs, Level 2 [Member] | Other Noncurrent Liabilities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Liabilities, Fair Value Disclosure | 318 | 6,590 |
Derivative Financial Instruments, Liabilities [Member] | Fair Value, Inputs, Level 3 [Member] | Accrued Liabilities [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Liabilities, Fair Value Disclosure | 0 | 0 |
Derivative Financial Instruments, Liabilities [Member] | Fair Value, Inputs, Level 3 [Member] | Other Noncurrent Liabilities | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Liabilities, Fair Value Disclosure | 0 | 0 |
Mutual Fund | Short-term Investments [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets, Fair Value Disclosure | 904 | 1,119 |
Mutual Fund | Other Noncurrent Assets [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets, Fair Value Disclosure | 19,606 | 14,657 |
Mutual Fund | Fair Value, Inputs, Level 1 [Member] | Short-term Investments [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets, Fair Value Disclosure | 904 | 1,119 |
Mutual Fund | Fair Value, Inputs, Level 1 [Member] | Other Noncurrent Assets [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets, Fair Value Disclosure | 19,606 | 14,657 |
Mutual Fund | Fair Value, Inputs, Level 2 [Member] | Short-term Investments [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets, Fair Value Disclosure | 0 | 0 |
Mutual Fund | Fair Value, Inputs, Level 2 [Member] | Other Noncurrent Assets [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets, Fair Value Disclosure | 0 | 0 |
Mutual Fund | Fair Value, Inputs, Level 3 [Member] | Short-term Investments [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets, Fair Value Disclosure | 0 | 0 |
Mutual Fund | Fair Value, Inputs, Level 3 [Member] | Other Noncurrent Assets [Member] | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | |
Assets, Fair Value Disclosure | $ 0 | $ 0 |