Cash, Cash Equivalents and Short-Term Investments

3 Months Ended

Mar. 31, 2019

Cash And Cash Equivalents [Abstract]

Cash, Cash Equivalents and Short-Term Investments

Note 4. Cash, Cash Equivalents and Short-Term Investments

The following tables show the Company’s cash and cash equivalents and short-term investments by significant investment category as of March 31, 2019 and December 31, 2018:

	March 31, 2019
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value		Cash and Cash Equivalents		Short-Term Investments
Cash	$	3,979,962	$	—	$	—		$	3,979,962	$	3,979,962	$	—
Level 1 (1):
Money market funds		4,766,828		—		—			4,766,828		4,766,828		—
U.S. treasury securities		4,976,466		1,209		—			4,977,675		—		4,977,675
Subtotal		9,743,294		1,209		—			9,744,503		4,766,828		4,977,675
Level 2 (2):
Commercial paper		8,065,664		—		—			8,065,664		—		8,065,664
Corporate debt obligations		3,701,311		616		(143	)		3,701,784		—		3,701,784
Repurchase agreements		3,000,630		—		—			3,000,630		3,000,630		—
Asset-backed securities		4,390,774		2,092		(362	)		4,392,504		—		4,392,504
Subtotal		19,158,379		2,708		(505	)		19,160,582		3,000,630		16,159,952
Total	$	32,881,635	$	3,917	$	(505	)	$	32,885,047	$	11,747,420	$	21,137,627

	December 31, 2018
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value		Cash and Cash Equivalents		Short-Term Investments
Cash	$	3,043,800	$	—	$	—		$	3,043,800	$	3,043,800	$	—
Level 1 (1):
Money market funds		5,481,647		—		—			5,481,647		5,481,647		—
U.S. treasury securities		1,987,794		—		(164	)		1,987,630		—		1,987,630
Subtotal		7,469,441		—		(164	)		7,469,277		5,481,647		1,987,630
Level 2 (2):
Commercial paper		10,639,390		—		—			10,639,390		2,094,983		8,544,407
Corporate debt obligations		5,963,913		—		(6,678	)		5,957,235		—		5,957,235
Repurchase agreements		3,000,226		—		—			3,000,226		3,000,226		—
Asset-backed securities		3,682,413		250		(2,954	)		3,679,709		—		3,679,709
Subtotal		23,285,942		250		(9,632	)		23,276,560		5,095,209		18,181,351
Total	$	33,799,183	$	250	$	(9,796	)	$	33,789,637	$	13,620,656	$	20,168,981

(1) Level 1 fair value estimates are based on quoted prices in active markets for identical assets or liabilities.

(2) Level 2 fair value estimates are based on observable inputs other than quoted prices in active markets for identical assets and liabilities, quoted prices for identical or similar assets or liabilities in inactive markets, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities.  

The Company’s investments were primarily valued based upon one or more valuations reported by its investment accounting and reporting service provider.  The investment service provider values the securities using a hierarchical security pricing model that relies primarily on valuations provided by a third-party pricing vendor.  Such valuations may be based on trade prices in active markets for identical assets or liabilities (Level 1 inputs) or valuation models using inputs that are observable either directly or indirectly (Level 2 inputs), such as quoted prices for similar assets or liabilities, yield curve, volatility factors, credit spreads, default rates, loss severity, current market and contractual prices for underlying instruments or debt, broker and dealer quotes, as well as other relevant economic measures.  The Company performs certain procedures to corroborate the fair value of its holdings, including comparing valuations obtained from its investment service provider with other pricing sources to validate the reasonableness of the valuations.    

The Company typically invests in highly-rated securities, and its investment policy limits the amount of credit exposure to any one issuer.  The policy requires investments in fixed income instruments denominated and payable in U.S. dollars only and requires investments to be investment grade, with a primary objective of minimizing the potential risk of principal loss.  

The following table presents the Company’s short-term investments with unrealized losses by investment category and length of time that individual securities have been in a continuous unrealized loss position as of March 31, 2019:

	Less Than 12 Months
Description of Securities	Estimated Fair Value		Unrealized Losses
Corporate debt obligations	$	1,492,290	$	(143	)
Asset-backed securities		749,732		(362	)
Total	$	2,242,022	$	(505	)

The Company considers the declines in market value of its short-term investments to be temporary in nature.  Fair values were determined for each individual security in the investment portfolio.  When evaluating an investment for other-than-temporary impairment, the Company reviews factors such as length of time and extent to which fair value has been below its cost basis, the financial condition of the issuer and any changes thereto, changes in market interest rates and the Company’s intent to sell, or whether it is more likely than not it will be required to sell the investment before recovery of the investment’s cost basis.  As of March 31, 2019, the Company does not consider any of its investments to be other-than temporarily impaired.

Contractual maturities of short-term investments as of March 31, 2019 are as follows:

	Estimated Fair Value
Due within one year	$	21,137,627
Total	$	21,137,627