Available-for-sale Securities and Fair Value on Financial Instruments (Tables)

3 Months Ended

Mar. 31, 2017

Fair Value Disclosures [Abstract]

Summary of Available-for-Sale Securities

The following is a summary of available-for-sale securities at March 31, 2017 (in thousands):

	March 31, 2017
	Amortized Cost		Gross Unrealized Gain		Gross Unrealized Loss			Fair Value
Money market funds	$	1,106	$	—	$	—		$	1,106
United States government agency securities		18,106		—		(18	)		18,088
Corporate debt securities		21,040		—		(10	)		21,030
Marketable equity securities		—		3,710		—			3,710
Total available-for-sale securities	$	40,252	$	3,710	$	(28	)	$	43,934

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

Available-for-Sale Debt Securities by Original Contractual Maturity

Available-for-sale securities at March 31, 2017 and December 31, 2016, consisted of the following by contractual maturity (in thousands):

	March 31, 2017				December 31, 2016
	Amortized Cost		Fair Value		Amortized Cost		Fair Value
One year or less	$	40,252	$	40,224	$	54,131	$	54,107
Marketable equity securities		—		3,710		—		3,952
Greater than one year and less than five years		—		—		—		—
Total available-for-sale securities	$	40,252	$	43,934	$	54,131	$	58,059

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):

	March 31, 2017
	Less than 12 Months					12 Months or Greater				Total
	Fair Value		Unrealized Loss			Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
United States government    agency securities	$	18,088	$	(18	)	$	—	$	—	$	18,088	$	(18	)
Corporate debt securities		18,030		(10	)		—		—		18,030		(10	)
Total available-for-sale    securities	$	36,118	$	(28	)	$	—	$	—	$	36,118	$	(28	)
	December 31, 2016
	Less than 12 Months					12 Months or Greater				Total
	Fair Value		Unrealized Loss			Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
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	)

Fair Values of Financial Assets and Liabilities

The fair values of the Company’s financial assets and liabilities were determined using the following inputs at March 31, 2017 (in thousands):

	Balance sheet			Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
	classification	Total		(Level 1)		(Level 2)		(Level 3)
Money market funds	Cash and cash equivalents	$	1,106	$	1,106	$	—	$	—
United States government agency securities	Short-term investments		18,088		—		18,088		—
Corporate debt securities	Short-term investments		21,030		—		21,030		—
Marketable equity securities	Marketable equity securities		3,710		3,710		—		—
Total financial assets		$	43,934	$	4,816	$	39,118	$	—

The fair values of the Company’s financial assets and liabilities were determined using the following inputs at December 31, 2016 (in thousands):

	Balance sheet			Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
	classification	Total		(Level 1)		(Level 2)		(Level 3)
Money market funds	Cash and cash equivalents	$	8,991	$	8,991	$	—	$	—
United States government agency securities	Short-term investments		8,029		—		8,029		—
Corporate debt securities	Short-term investments		37,087		—		37,087		—
Marketable equity securities	Marketable equity securities		3,952		3,952		-		—
Total financial assets		$	58,059	$	12,943	$	45,116	$	—