Cash and Cash Equivalents and Investments (Details 1) - USD ($) $ in Thousands |
Sep. 30, 2019 |
Dec. 31, 2018 |
---|---|---|
Cash and Cash Equivalents | ||
Fair Value | ||
Amortized Cost | $ 170,203 | $ 80,386 |
Gross Unrealized Gains | 0 | 0 |
Gross Unrealized Losses | 0 | 0 |
Estimated Fair Value | 170,203 | 80,386 |
U.S. Treasury Securities | ||
Fair Value | ||
Amortized Cost | 126,065 | 73,983 |
Gross Unrealized Gains | 44 | 0 |
Gross Unrealized Losses | (8) | (9) |
Estimated Fair Value | 126,101 | 73,974 |
Corporate Debt Securities | ||
Fair Value | ||
Amortized Cost | 5,695 | |
Gross Unrealized Gains | 0 | |
Gross Unrealized Losses | (3) | |
Estimated Fair Value | 5,692 | |
Total Short-term Investments | ||
Fair Value | ||
Amortized Cost | 126,065 | 79,678 |
Gross Unrealized Gains | 44 | 0 |
Gross Unrealized Losses | (8) | (12) |
Estimated Fair Value | 126,101 | 79,666 |
Total Cash and Cash Equivalents and Investments | ||
Fair Value | ||
Amortized Cost | 296,268 | 160,064 |
Gross Unrealized Gains | 44 | 0 |
Gross Unrealized Losses | (8) | (12) |
Estimated Fair Value | $ 296,304 | $ 160,052 |