Investments	3 Months Ended
Mar. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Investments	NOTE 4 – INVESTMENTS Cash and cash equivalents includes investments in money market funds that are valued based on the net asset value of the funds. The cash equivalents consist primarily of money market funds that are Level 1 measurements. The investments in these funds were $17 thousand and $55.6 million as of March 31, 2018 and December 31, 2017, respectively. All other investments are classified as held-to-maturity and consist of highly liquid instruments, primarily including corporate bonds and commercial paper. As of March 31, 2018 and December 31, 2017, the amortized cost of these investments equaled the net carrying value, which was $28.8 million and $30.1 million, respectively. All held-to-maturity securities as of March 31, 2018 mature in one year or less. See Note 7, Fair Value Measurements, for additional information.

Investments

3 Months Ended

Mar. 31, 2018

Investments, Debt and Equity Securities [Abstract]

NOTE 4 – INVESTMENTS

Cash and cash equivalents includes investments in money market funds that are valued based on the net asset value of the funds. The cash equivalents consist primarily of money market funds that are Level 1 measurements. The investments in these funds were $17 thousand and $55.6 million as of March 31, 2018 and December 31, 2017, respectively.

All other investments are classified as held-to-maturity and consist of highly liquid instruments, primarily including corporate bonds and commercial paper. As of March 31, 2018 and December 31, 2017, the amortized cost of these investments equaled the net carrying value, which was $28.8 million and $30.1 million, respectively. All held-to-maturity securities as of March 31, 2018 mature in one year or less. See Note 7, Fair Value Measurements, for additional information.