Fair Value Measurements

12 Months Ended

Dec. 31, 2018

Fair Value Disclosures [Abstract]

Fair Value Measurements

12. Fair Value Measurements

The carrying amounts of certain financial instruments, including cash and cash equivalents, prepaid expenses and other current assets, accounts payable, and accrued expenses approximate their respective fair values due to the short-term nature of such instruments.

Assets and Liabilities Measured at Fair Value on a Recurring Basis

The Company evaluates its financial assets and liabilities subject to fair value measurements on a recurring basis to determine the appropriate level in which to classify them for each reporting period, pursuant to the policy described in Note 2. This determination requires significant judgments to be made. The following table summarizes the conclusions reached as of December 31, 2018 and 2017 for financial instruments measured at fair value on a recurring basis (in thousands):

			Fair Value Hierarchy Classification
	Balance		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
December 31, 2017
Cash on deposit	$	1,316	$	1,316		—		—
Money market funds		10,153		10,153		—		—
Total assets	$	11,469	$	11,469		—		—
Warrant liability	$	3,872		—		—	$	3,872
Total liabilities	$	3,872	$	—		—	$	3,872
December 31, 2018
Cash	$	213	$	213		—		—
Restricted cash		328		328		—		—
Money market funds		11,226		11,226		—		—
Total assets	$	11,767	$	11,767		—		—
Warrant liability	$	986		—		—	$	986
Total liabilities	$	986		—		—	$	986

The Company measures cash equivalents at fair value on a recurring basis. The fair value of cash equivalents is determined based on “Level 1” inputs, which consist of quoted prices in active markets for identical assets.

Level 3 financial liabilities consist of the warrant liability for which there is no current market such that the determination of fair value requires significant judgment or estimation. Changes in fair value measurements categorized within Level 3 of the fair value hierarchy are analyzed each period based on changes in estimates or assumptions and recorded as appropriate. The Company uses the Black-Scholes option valuation model to value the Level 3 warrant liability at inception and on subsequent valuation dates. This model incorporates transaction details such as the Company’s stock price, contractual terms, maturity, risk free rates, as well as volatility.

A reconciliation of the beginning and ending balances for liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3) is as follows (in thousands):

	December 31, 2018
Balance - January 1, 2018	$	3,872
March 2018 Public Offering - Series 1 Warrants		3,480
March 2018 Public Offering - Series 2 Warrants		5,500
Gain adjustment to fair value		(11,866	)
Balance - December 31, 2018	$	986