Available-for-sale Securities (Tables)

12 Months Ended

Dec. 31, 2016

Investments Debt And Equity Securities [Abstract]

Summary of Available-for-Sale Securities

The following is a summary of available-for-sale securities at December 31, 2016 (in thousands):

	December 31, 2016
	Amortized Cost		Gross Unrealized Gain		Gross Unrealized Loss			Fair Value
Money market funds	$	8,991	$	—	$	—		$	8,991
United States government agency securities		8,030		—		(1	)		8,029
Corporate debt securities		37,110		—		(23	)		37,087
Marketable equity securities		—		3,952		—			3,952
Total available-for-sale securities	$	54,131	$	3,952	$	(24	)	$	58,059

The following is a summary of available-for-sale securities at December 31, 2015(in thousands):

	December 31, 2015
	Amortized Cost		Gross Unrealized Gain		Gross Unrealized Loss			Fair Value
Money market funds	$	59,302	$	—	$	—		$	59,302
Corporate debt securities		25,747		—		(49	)		25,698
Marketable equity securities		—		11,163		—			11,163
Total available-for-sale securities	$	85,049	$	11,163	$	(49	)	$	96,163

Available-for-Sale Debt Securities by Original Contractual Maturity

Available-for-sale securities at December 31, 2016 and 2015, consisted of the following by contractual maturity (in thousands):

	December 31, 2016				December 31, 2015
	Amortized Cost		Fair Value		Amortized Cost		Fair Value
One year or less	$	54,131	$	54,107	$	85,049	$	85,000
Marketable equity securities		—		3,952		—		11,163
Greater than one year and less than five years		—		—		—		—
Total available-for-sale securities	$	54,131	$	58,059	$	85,049	$	96,163

Available-for-Sale Marketable Securities in Unrealized Position

The following tables show all available-for-sale marketable securities in an unrealized loss position for which an other-than-temporary impairment has not been recognized and the related gross unrealized losses and fair value, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position (in thousands):

	December 31, 2016
	Less than 12 Months					12 Months or Greater				Total
	Fair Value		Unrealized Loss			Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
Money market funds	$	—	$	—		$	—	$	—	$	—	$	—
United States government    agency securities		6,035		(1	)		—		—		6,035		(1	)
Corporate debt securities		34,086		(23	)		—		—		34,086		(23	)
Total available-for-sale    securities	$	40,121	$	(24	)	$	—	$	—	$	40,121	$	(24	)

	December 31, 2015
	Less than 12 Months					12 Months or Greater					Total
	Fair Value		Unrealized Loss			Fair Value		Unrealized Loss			Fair Value		Unrealized Loss
Money market funds	$	—	$	—		$	—	$	—		$	—	$	—
United States government    agency securities		—		—			—		—			—		—
Corporate debt securities		20,170		(46	)		5,528		(3	)		25,698		(49	)
Total available-for-sale    securities	$	20,170	$	(46	)	$	5,528	$	(3	)	$	25,698	$	(49	)