Concentration of Credit Risk

12 Months Ended

Dec. 31, 2016

Risks And Uncertainties [Abstract]

Concentration of Credit Risk

2. Concentration of Credit Risk

Financial instruments that potentially subject us to concentration of credit risk consist primarily of cash equivalents, investments, restricted cash and investments, and trade accounts receivable. We limit investment of cash equivalents and investments to financial institutions with high credit ratings. Credit risk on trade accounts is minimized as a result of the large and diverse nature of our customer base.

At December 31, 2016, we had concentrations of credit risk as follows:

• $286.5 million, at fair value, in money market funds.

• $10.8 million, at fair value, in certificates of deposit.