Investments

Investments at March 31, 2019 and December 31, 2018 consisted of mutual funds and United States corporate debt securities. Investments are recorded at fair value, based on current market valuations. Unrealized gains and losses on the Company's debt securities will continue to be excluded from earnings and are reported as a separate component of other comprehensive loss until realized. Realized gains and losses are included in non-operating other income (expense) on the condensed consolidated statement of operations and are derived using the specific identification method for determining the cost of the securities sold. During the three months ended March 31, 2019 and 2018, $36,000 and $253,000, respectively, of net realized loss on investments was recorded. The Company assessed each of its investments on an individual basis to determine if any decline in fair value was other-than-temporary. Interest and dividends on investments classified as available-for-sale are included in interest and other income, net, in the condensed consolidated statements of operations. As of March 31, 2019, the Company had three available-for-sale securities with an aggregate total unrealized loss of $31,000 which were in such position for longer than 12 months.

The following is a summary of available-for-sale securities as of March 31, 2019 and December 31, 2018:



		As of March 31, 2019
	Contractual Maturity (in years)	Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Market Value
Mutual funds	---	$	106,483,816	$	539,170	$	(31,229	)	$	106,991,757
US corporate debt securities	Less than 2	224,578		376		(213		)	224,741
Total investments		$	106,708,394	$	539,546	$	(31,442	)	$	107,216,498



		As of December 31, 2018
	Contractual Maturity (in years)	Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Market Value
Mutual funds	---	$	57,842,955	$	—	$	(528,084	)	$	57,314,871
US corporate debt securities	Less than 2	224,633		—		(652		)	223,981
Total investments		$	58,067,588	$	—	$	(528,736	)	$	57,538,852