Financial Instruments

3 Months Ended

Mar. 31, 2018

Financial Instruments

Financial Instruments

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:

	March 31, 2018								December 31, 2017
	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	$	21,349	$	—	$	—	$	21,349	$	3,477	$	—	$	—	$	3,477
U.S. Treasury securities		46,496		1		(577)		45,920		67,480		10		(464)		67,026
U.S. agency securities		22,562		—		(233)		22,329		27,293		—		(221)		27,072
Municipal securities		11,869		—		(95)		11,774		12,240		—		(91)		12,149
Total	$	102,276	$	1	$	(905)	$	101,372	$	110,490	$	10	$	(776)	$	109,724
Classified as:
Cash equivalents							$	21,349							$	3,477
Short-term investments								80,023								106,247
Total							$	101,372							$	109,724

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 three months ended March 31, 2018 and 2017,  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 March 31, 2018, the Company had 17 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 March 31, 2018:

	March 31, 2018
	Amortized Cost		Fair Value
	(in thousands)
Less than one year	$	39,157	$	39,021
Greater than one year but less than five years		41,770		41,002
Total	$	80,927	$	80,023