FAIR VALUE MEASUREMENTS (Tables)

9 Months Ended

12 Months Ended

Sep. 30, 2019

Dec. 31, 2018

FAIR VALUE MEASUREMENTS

Schedule of financial assets or liabilities measured at fair value on a recurring basis

As of December 31, 2018, the Company did not have financial assets or liabilities that are measured at fair value on a recurring basis (in thousands).

	As of September 30, 2019
	Level 1		Level 2		Level 3		Total
Cash	$	12,933	$	—	$	—	$	12,933
Money market funds		133		—		—		133
Total cash and cash equivalents	$	13,065	$	—	$	—	$	13,065
Commercial paper and corporate bonds		—		7,522		—		7,522
U.S. government agency debt securities		—		12,367		—		12,367
Total marketable securities	$	—	$	19,889	$	—	$	19,889
Total financial assets measured at fair value on a recurring basis	$	13,065	$	19,889	$	—	$	32,954

Schedule of Company’s Derivative Liability and Warrant Liability

The following table provides a roll forward of the aggregate fair values of the Derivative Liability and Warrant Liability as of September 30, 2018, for which fair value is determined using Level 3 inputs (in thousands):

	Derivative		Warrant
	Liability		Liability
Balance as of January 1, 2018	$	—	$	—
Initial fair value of Derivative Liability		1,896		—
Initial fair value of Warrant Liability		—		74
Change in fair value		180		6
Balance as of March 31, 2018	$	2,076	$	80
Change in fair value		294		21
Balance as of June 30, 2018	$	2,370	$	101
Change in fair value		335		38
Balance as of September 30, 2018	$	2,704	$	139

The following table provides a roll forward of the aggregate fair values of the Company’s Derivative Liability and Warrant Liability, for which fair value is determined using Level 3 inputs (in thousands):

	Derivative		Warrant
	Liability		Liability
Balance as of January 1, 2018	$	—	$	—
Initial fair value of Derivative Liability		1,896		—
Initial fair value of Warrant Liability		—		74
Change in fair value		972		168
Extinguishment of Derivative Liability in connection with extinguishment of 2018 Notes		(2,868)		—
Reclassification of Warrant Liability into 2018 Notes Warrants		—		(242)
Balance as of December 31, 2018	$	—	$	—