Investment Securities

12 Months Ended

Dec. 31, 2017

Investments, Debt and Equity Securities [Abstract]

Investment Securities

Investment Securities

Investment securities, available-for-sale consisted of the following (in thousands):

	Amortized cost		Gross unrealized gains		Gross unrealized losses			Fair value (net carrying amount)
As of December 31, 2017
Domestic and foreign corporate bonds	$	328,747	$	6	$	(1,298	)	$	327,455
As of December 31, 2016
Domestic and foreign corporate bonds	$	245,425	$	19	$	(720	)	$	244,724
Commercial paper	56,764		5		(33		)	56,736
Total	$	302,189	$	24	$	(753	)	$	301,460

For investments with unrealized losses as of December 31, 2017, the Company has determined that (i) it does not have the intent to sell any of these investments, and (ii) it is not likely that the Company will be required to sell these investments prior to the recovery of the amortized cost. Accordingly, the Company has determined that no other-than-temporary impairments exist at the reporting date.

The Company obtains pricing information in determining the fair value of its available-for-sale securities from independent pricing vendors. Based on management's inquiries, the pricing vendors use various pricing models consistent with what other market participants would use. The assumptions and inputs used by the pricing vendors are derived from market observable sources including: reported trades, broker/dealer quotes, issuer spreads, benchmark curves, bids, offers and other market-related data. The Company has not made adjustments to such prices. Each quarter, the Company validates the fair value pricing methodology to determine the fair value is consistent with applicable accounting guidance and to confirm that the securities are classified properly in the fair value hierarchy. The Company compares the pricing received from its vendors to independent sources for the same or similar securities.

The fair value of these investment securities as of December 31, 2017, by contractual maturity, are as follows (in thousands):

	Fair value
Available-for-sale securities
Due in one year or less	$	166,773
Due after one year through two years	118,280
Due after two years through three years	42,402
	$	327,455

Investment Securities

Investment securities, available-for-sale consisted of the following (in thousands):

	Amortized cost		Gross unrealized gains		Gross unrealized losses			Fair value (net carrying amount)
As of December 31, 2017
Domestic and foreign corporate bonds	$	328,747	$	6	$	(1,298	)	$	327,455
As of December 31, 2016
Domestic and foreign corporate bonds	$	245,425	$	19	$	(720	)	$	244,724
Commercial paper	56,764		5		(33		)	56,736
Total	$	302,189	$	24	$	(753	)	$	301,460

For investments with unrealized losses as of December 31, 2017, the Company has determined that (i) it does not have the intent to sell any of these investments, and (ii) it is not likely that the Company will be required to sell these investments prior to the recovery of the amortized cost. Accordingly, the Company has determined that no other-than-temporary impairments exist at the reporting date.

The Company obtains pricing information in determining the fair value of its available-for-sale securities from independent pricing vendors. Based on management's inquiries, the pricing vendors use various pricing models consistent with what other market participants would use. The assumptions and inputs used by the pricing vendors are derived from market observable sources including: reported trades, broker/dealer quotes, issuer spreads, benchmark curves, bids, offers and other market-related data. The Company has not made adjustments to such prices. Each quarter, the Company validates the fair value pricing methodology to determine the fair value is consistent with applicable accounting guidance and to confirm that the securities are classified properly in the fair value hierarchy. The Company compares the pricing received from its vendors to independent sources for the same or similar securities.

The fair value of these investment securities as of December 31, 2017, by contractual maturity, are as follows (in thousands):

	Fair value
Available-for-sale securities
Due in one year or less	$	166,773
Due after one year through two years	118,280
Due after two years through three years	42,402
	$	327,455