Short-term Investment Securities	6 Months Ended
Jun. 30, 2020
Investments, Debt and Equity Securities [Abstract]
Short-term Investment Securities	Short-term Investment SecuritiesThe Company's short-term investment securities are classified as available-for-sale and generally consist of U.S. Treasury and U.S. government agency securities with contractual maturities of 12 months or less. These securities are stated at fair value within current assets on the Company's condensed balance sheets. Realized gains and losses on sales of investments, if any, are reflected in non-operating income (expense) in the condensed statements of operations. As of June 30, 2020 and December 31, 2019, the Company had $106.3 million and $105.3 million in short-term available-for-sale investment securities, respectively. During the six months ended June 30, 2020, these investments earned interest income at a weighted-average fixed rate of approximately 1.5%. For the three and six months ended June 30, 2020, an unrealized loss and an unrealized gain of $199 thousand and $123 thousand, respectively, net of deferred taxes of $59 thousand and $36 thousand, respectively, was recorded within accumulated other comprehensive income ("AOCI") related to these investment securities. For the three and six months ended June 30, 2019, an unrealized gain of $98 thousand and $228 thousand, respectively, net of deferred taxes of $29 thousand and $67 thousand, respectively, was recorded within AOCI related to these investment securities. For the three and six months ended June 30, 2020, the Company had substantially no realized gains or losses related to these securities. For the three and six months ended June 30, 2019, the Company had no realized gains or losses as the Company did not sell any of these securities during these periods. As of June 30, 2020 and December 31, 2019, $227 thousand and $104 thousand, net of tax, respectively, remained in AOCI, related to these instruments.

Short-term Investment Securities

6 Months Ended

Jun. 30, 2020

Investments, Debt and Equity Securities [Abstract]

Short-term Investment SecuritiesThe Company's short-term investment securities are classified as available-for-sale and generally consist of U.S. Treasury and U.S. government agency securities with contractual maturities of 12 months or less. These securities are stated at fair value within current assets on the Company's condensed balance sheets. Realized gains and losses on sales of investments, if any, are reflected in non-operating income (expense) in the condensed statements of operations. As of June 30, 2020 and December 31, 2019, the Company had $106.3 million and $105.3 million in short-term available-for-sale investment securities, respectively. During the six months ended June 30, 2020, these investments earned interest income at a weighted-average fixed rate of approximately 1.5%. For the three and six months ended June 30, 2020, an unrealized loss and an unrealized gain of $199 thousand and $123 thousand, respectively, net of deferred taxes of $59 thousand and $36 thousand, respectively, was recorded within accumulated other comprehensive income ("AOCI") related to these investment securities. For the three and six months ended June 30, 2019, an unrealized gain of $98 thousand and $228 thousand, respectively, net of deferred taxes of $29 thousand and $67 thousand, respectively, was recorded within AOCI related to these investment securities. For the three and six months ended June 30, 2020, the Company had substantially no realized gains or losses related to these securities. For the three and six months ended June 30, 2019, the Company had no realized gains or losses as the Company did not sell any of these securities during these periods. As of June 30, 2020 and December 31, 2019, $227 thousand and $104 thousand, net of tax, respectively, remained in AOCI, related to these instruments.