Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2018

Fair Value Disclosures [Abstract]

Assets and Liabilities Carried at Fair Value and Measured on Recurring Basis

The fair value hierarchy of the Company’s financial assets and liabilities carried at fair value and measured on a recurring basis is as follows:

			Fair Value Measurements at Reporting Date Using
	December 31, 2018		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Money market funds(1)	$	15,070	$	15,070	$	—	$	—
Short-term investments(2)		500		—		500		—
Long-term investments(2)		—		—		—		—
Total assets	$	15,570	$	15,070	$	500	$	—

			Fair Value Measurements at Reporting Date Using
	December 31, 2017		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Money market funds(1)	$	7,155	$	7,155	$	—	$	—
Short-term investments(2)		7,650		—		7,650		—
Long-term investments(2)		496		—		496		—
Total assets	$	15,301	$	7,155	$	8,146	$	—

(1) Included in cash and cash equivalents on the accompanying consolidated balance sheets; valued at quoted market prices in active markets.

(2) Short-term and long-term investments consist of municipal bonds, corporate bonds, U.S. Treasury securities, and government agency bonds; their fair value is calculated using an interest rate yield curve for similar instruments.