Fair Value Measurements (Tables)

6 Months Ended

Jun. 30, 2019

Fair Value Disclosures [Abstract]

Schedule of Financial Assets and Liabilities at Fair value on a Recurring Basis

The Company measures the following financial assets at fair value on a recurring basis. There were no transfers between levels of the fair value hierarchy during any of the periods presented. The following tables set forth the Company’s financial assets carried at fair value categorized using the lowest level of input applicable to each financial instrument as of June 30, 2019 and December 31, 2018 (in thousands):

	Balance at June 30, 2019		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Cash	$	14,181	$	14,181	$	—	$	—
Money market funds		14,241		14,241		—		—
Restricted cash		180		180		—		—
	$	28,602	$	28,602	$	—	$	—
Liabilities:
Derivative liability	$	2,503	$	—	$	—	$	2,503
	$	2,503	$	—	$	—	$	2,503

	Balance at December 31, 2018		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Cash	$	6,868	$	6,868	$	—	$	—
Money market funds		43,937		43,937		—		—
Restricted cash		180		180		—		—
	$	50,985	$	50,985	$	—	$	—
Liabilities:
Derivative liability	$	2,142	$	—	$	—	$	2,142
	$	2,142	$	—	$	—	$	2,142

Roll-Forward of Fair Value of Derivative Liability

The following table provides a roll-forward of the fair value of the derivative liability (in thousands):

Balance at December 31, 2018	$	2,142
Change in fair value of derivative liability, recorded as interest expense		361
Balance at June 30, 2019	$	2,503