Fair Value of Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2019

Fair Value Disclosures [Abstract]

Summary of Financial Instruments Measured at Fair Value on Recurring Basis

The following table sets forth the Company’s financial instruments that were measured at fair value on a recurring basis by level within the fair value hierarchy (in thousands).

	Fair Value Measurements at December 31, 2019
	Total		Level 1		Level 2		Level 3
Liabilities
2017 PIPE warrant liability	$	10,822	$	—	$	—	$	10,822
2018 PIPE warrant liability		1,354		—		—		1,354
Essentialis purchase price contingency liability		5,938		—		—		5,938
Total common stock warrant and contingent    consideration liability	$	18,114	$	-	$	—	$	18,114

	Fair Value Measurements at December 31, 2018
	Total		Level 1		Level 2		Level 3
Liabilities
Series A warrant liability	$	49	$	49	$	—	$	—
2017 PIPE warrant liability		4,563		—		—		4,563
2018 PIPE warrant liability		600		—		—		600
Essentialis purchase price contingency liability		5,649		—		—		5,649
Total common stock warrant and contingent    consideration liability	$	10,861	$	49	$	-	$	10,812

Summary of Changes in Fair Value of Level1 and Level 3 Financial Instruments

The following table sets forth a summary of the changes in the fair value of the Company’s Level 1 and Level 3 warrants, which are treated as liabilities (dollars in thousands).

	Series A Warrants						Series C Warrants				2017 PIPE Warrants				2018 PIPE Warrants				Purchase Price
	Number of Warrants			Liability			Number of Warrants		Liability		Number of Warrants		Liability		Number of Warrants		Liability		Contingent Liability
Balance at January 1, 2019		485,121		$	49			118,083	$	—		6,024,425	$	4,563		513,617	$	600	$	5,649
Expiration of Series A Warrants		(485,121	)		(49	)		—		—		—		—		—		—		—
Change in value of Series C Warrants		—						—		—		—		—		—		—		—
Change in value of 2017 PIPE Warrants		—			—			—		—		—		6,259		—		—		—
Change in value of 2018 PIPE Warrants		—			—			—		—		—		—		—		754		—
Change in value of contingent liability		—			—			—		—		—		—		—		—		289
Balance at December 31, 2019		—		$	—			118,083	$	—		6,024,425	$	10,822		513,617	$	1,354	$	5,938