Investments (Tables)

12 Months Ended

Dec. 31, 2017

Investments, Debt and Equity Securities [Abstract]

Schedule of Amortized Cost, Unrealized Gains and Losses and Fair Value of Investments Available-for-Sale

The amortized cost, unrealized gains and losses and fair value of investments available-for-sale as of December 31, 2017 are as follows:

	Amortized Cost		Unrealized Gain		Unrealized Loss			Fair Value
Corporate bonds and notes—short-term	$	21,946	$	—	$	(2	)	$	21,944
Total investments	$	21,946	$	—	$	(2	)	$	21,944

The amortized cost, unrealized gains and losses and fair value of investments available-for-sale as of December 31, 2016 are as follows:

	Amortized Cost		Unrealized Gain		Unrealized Loss			Fair Value
Corporate bonds and notes—short-term	$	18,451	$	2	$	(6	)	$	18,447
Total investments	$	18,451	$	2	$	(6	)	$	18,447