Quarterly report pursuant to Section 13 or 15(d)

Summary of Cash, Cash Equivalents and Marketable Securities (Details)

v3.21.1
Summary of Cash, Cash Equivalents and Marketable Securities (Details) - USD ($)
$ in Thousands
 3 Months Ended 12 Months Ended
Mar. 31, 2021
Dec. 31, 2020
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Available-for-sale Securities, Amortized Cost Basis $ 37,147 $ 46,019
Available-for-sale Securities, Gross Unrealized Gain 139 228
Available-for-sale Securities, Gross Unrealized Loss (2)
Available-for-sale Securities 37,284 46,247
U.S. Treasury Bonds [Member]    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Available-for-sale Securities, Amortized Cost Basis 17,570 18,293
Available-for-sale Securities, Gross Unrealized Gain 81 136
Available-for-sale Securities, Gross Unrealized Loss
Available-for-sale Securities 17,651 18,429
U.S. Government Notes [Member]    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Available-for-sale Securities, Amortized Cost Basis 14,234 22,148
Available-for-sale Securities, Gross Unrealized Gain 54 82
Available-for-sale Securities, Gross Unrealized Loss (1)
Available-for-sale Securities 14,287 22,230
Corporate Debt Securities [Member]    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Available-for-sale Securities, Amortized Cost Basis 4,068 4,303
Available-for-sale Securities, Gross Unrealized Gain 3
Available-for-sale Securities, Gross Unrealized Loss (1)
Available-for-sale Securities 4,067 4,306
State and Municipal Bonds [Member]    
Fair Value Measurement Inputs and Valuation Techniques [Line Items]    
Available-for-sale Securities, Amortized Cost Basis 1,275 1,275
Available-for-sale Securities, Gross Unrealized Gain 4 7
Available-for-sale Securities, Gross Unrealized Loss
Available-for-sale Securities $ 1,279 $ 1,282