Investments	3 Months Ended
Mar. 31, 2020
Investments
Investments	7. Investments During the third quarter of 2016, the Company purchased a minority interest in preferred stock in a privately held company for $0.3 million. During the third quarter of 2018, the Company was issued a convertible note by a privately held company having a principal amount of $0.2 million. The preferred stock investment is recorded on a cost basis in other non-current assets on the accompanying balance sheets as the Company does not have a controlling interest, does not have the ability to exercise significant influence over the privately held company, and the fair value of the equity investment is not readily determinable. The Company performs an impairment analysis at each reporting period to determine if there is any readily available fair value information that would indicate an impairment. The Company has determined there was no impairment during the three months ended March 31, 2020 or in any prior period. The convertible note is held as an available-for-sale investment, which is carried at fair market value, with the unrealized gains and losses included in the determination of comprehensive income and reporting stockholders equity. When determining the estimated fair value of the convertible notes, the Company used a commonly accepted valuation methodology. Equity investments that do not result in consolidation and are not accounted for under the equity method are measured at fair value, with any changes in fair value recognized in net income. For any such investments that do not have readily determinable fair values, the Company elects the measurement alternative to measure the investments at cost minus impairment, if any, plus or minus changes resulting from observable price changes in orderly transactions for the identical or a similar investment of the same issuer.

7. Investments

During the third quarter of 2016, the Company purchased a minority interest in preferred stock in a privately held company for $0.3 million. During the third quarter of 2018, the Company was issued a convertible note by a privately held company having a principal amount of $0.2 million.

The preferred stock investment is recorded on a cost basis in other non-current assets on the accompanying balance sheets as the Company does not have a controlling interest, does not have the ability to exercise significant influence over the privately held company, and the fair value of the equity investment is not readily determinable. The Company performs an impairment analysis at each reporting period to determine if there is any readily available fair value information that would indicate an impairment. The Company has determined there was no impairment during the three months ended March 31, 2020 or in any prior period.

The convertible note is held as an available-for-sale investment, which is carried at fair market value, with the unrealized gains and losses included in the determination of comprehensive income and reporting stockholders equity. When determining the estimated fair value of the convertible notes, the Company used a commonly accepted valuation methodology.

Equity investments that do not result in consolidation and are not accounted for under the equity method are measured at fair value, with any changes in fair value recognized in net income. For any such investments that do not have readily determinable fair values, the Company elects the measurement alternative to measure the investments at cost minus impairment, if any, plus or minus changes resulting from observable price changes in orderly transactions for the identical or a similar investment of the same issuer.