Fair Value Measurements (Fair Value Hierarchy for Assets and Liabilities Measured at Fair Value on Recurring Basis) (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets measured at fair value on a recurring basis	$ 49,911	$ 57,905
Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets measured at fair value on a recurring basis	49,911	57,905
Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets measured at fair value on a recurring basis	0	0
Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets measured at fair value on a recurring basis	0	0
Cash equivalents (money market funds)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets measured at fair value on a recurring basis	49,911	57,905
Cash equivalents (money market funds) | Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets measured at fair value on a recurring basis	49,911	57,905
Cash equivalents (money market funds) | Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets measured at fair value on a recurring basis	0	0
Cash equivalents (money market funds) | Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets measured at fair value on a recurring basis	$ 0	$ 0