Financial Instruments

6 Months Ended

Jun. 30, 2019

5. Financial Instruments

The Company elected to invest a portion of its cash assets in conservative, income earning, and liquid investments. Cash equivalents and investments, all of which are classified as available-for-sale securities, consisted of the following:


	June 30, 2019								December 31, 2018
	Amortized Cost		Gross Unrealized Gain		Gross Unrealized Loss		Estimated Fair Value		Amortized Cost		Gross Unrealized Gain		Gross Unrealized Loss		Estimated Fair Value
	(in thousands)
Money market deposits	$	630	$	—	$	—	$	630	$	26,539	$	—	$	—	$	26,539
U.S. Treasury securities		158,429		733		(65)		159,097		76,061		29		(405)		75,685
U.S. agency securities		13,004		—		(27)		12,977		13,017		—		(126)		12,891
Municipal securities		35,825		162		(8)		35,979		18,935		7		(57)		18,885
Total	$	207,888	$	895	$	(100)	$	208,683	$	134,552	$	36	$	(588)	$	134,000

Classified as:
Cash equivalents							$	630							$	26,539
Short-term investments								208,053								107,461
Total							$	208,683							$	134,000

The Company invests in U.S. Treasuries, U.S. agency and high quality municipal bonds which mature at par value and are all paying their coupons on schedule. The Company has therefore concluded there is currently no other than temporary impairment of its investments and will continue to recognize unrealized gains and losses in other comprehensive income (loss). During the six months ended June 30, 2019, there were no sales of investments, and during the six months ended June 30, 2018, the amount of gross realized gains and realized losses upon sales of investments were insignificant. The Company uses the specific investment identification method to calculate realized gains and losses and amounts reclassified out of other comprehensive income to net income. As of June 30, 2019, the Company had 7 investments in an unrealized loss position in its portfolio.

The following table summarizes the Company’s portfolio of available-for-sale securities by contractual maturity as of June 30, 2019:


	June 30, 2019
	Amortized Cost		Fair Value
	(in thousands)
Less than one year	$	97,180	$	97,276
Greater than one year but less than five years		110,077		110,777
Total	$	207,257	$	208,053