Investments

Investments at June 30, 2019 consisted of mutual funds. Investments at 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 and six months ended June 30, 2019, $129,000 and $93,000, respectively, of net realized gain on investments was recorded. During the three and six months ended June 30, 2018, $(121,000) and $(374,000), respectively, of net realized loss on investments was recorded. 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 June 30, 2019, the Company had no available-for-sale securities in an unrealized loss position for longer than 12 months.

The following is a summary of available-for-sale securities as of June 30, 2019 and December 31, 2018:



		As of June 30, 2019
	Contractual Maturity (in years)	Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Market Value
Mutual funds	---	$	85,168,756	$	1,067,059	$	—	$	86,235,815



		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