Available-for-sale Securities and Fair Value on Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2020

Fair Value Disclosures [Abstract]

Summary of Available-for-Sale Securities

The following is a summary of available-for-sale securities at December 31, 2020 (in thousands):

	December 31, 2020
	Amortized Cost		Gross Unrealized Gain		Gross Unrealized Loss			Allowance for Credit Loss		Fair Value
Money market funds	$	6,203	$	—	$	—		$	—	$	6,203
United States government agency securities		29,570		66		—			—		29,636
Corporate debt securities		66,756		611		(3	)		—		67,364
Total available-for-sale securities	$	102,529	$	677	$	(3	)	$	—	$	103,203

The following is a summary of available-for-sale securities at December 31, 2019 (in thousands):

	December 31, 2019
	Amortized Cost		Gross Unrealized Gain		Gross Unrealized Loss		Allowance for Credit Loss		Fair Value
Money market funds	$	8,860	$	—	$	—	$	—	$	8,860
United States government agency securities		15,545		16		—		—		15,561
Corporate debt securities		35,073		98		—		—		35,171
Total available-for-sale securities	$	59,478	$	114	$	—	$	—	$	59,592

Available-for-Sale Debt Securities by Original Contractual Maturity

Available-for-sale securities at December 31, 2020 and December 31, 2019, consisted of the following by contractual maturity (in thousands):

	December 31, 2020				December 31, 2019
	Amortized Cost		Fair Value		Amortized Cost		Fair Value
One year or less	$	64,857	$	65,117	$	43,822	$	43,907
Greater than one year and less than five years		37,672		38,086		15,656		15,685
Total available-for-sale securities	$	102,529	$	103,203	$	59,478	$	59,592

Available-for-Sale Marketable Securities in Unrealized Position

The following table shows all available-for-sale marketable securities in an unrealized loss position for which an allowance for credit losses has not been recognized and the related gross unrealized losses and fair value, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position (in thousands):

	December 31, 2020
	Less than 12 Months					12 Months or Greater				Total
	Fair Value		Unrealized Loss			Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
Corporate debt securities	$	5,105	$	(3	)	$	—	$	—	$	5,105	$	(3	)

Fair Values of Financial Assets and Liabilities

The fair values of the Company’s financial assets and liabilities were determined using the following inputs at December 31, 2020 (in thousands):

	Balance sheet			Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
	classification	Total		(Level 1)		(Level 2)		(Level 3)
Money market funds	Cash and cash equivalents	$	6,203	$	6,203	$	—	$	—
United States government agency securities	Short-term investments		30,683		—		30,683		—
Corporate debt securities	Short-term investments		66,317		—		66,317		—
Total short-term investments			103,203		6,203		97,000		—
Warrants	Other assets		422						422
Total financial assets		$	103,625	$	6,203	$	97,000	$	422

The fair values of the Company’s financial assets and liabilities were determined using the following inputs at December 31, 2019 (in thousands):

	Balance sheet			Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
	classification	Total		(Level 1)		(Level 2)		(Level 3)
Money market funds	Cash and cash equivalents	$	8,860	$	8,860	$	—	$	—
United States government agency securities	Short-term investments		15,561		—		15,561		—
Corporate debt securities	Short-term investments		35,171		—		35,171		—
Total financial assets		$	59,592	$	8,860	$	50,732	$	—

Summary of Gain Recognized in Consolidated Statements of Operations Due to Changes in Fair Value of Warrant

The following table provides a summary of the total gain recognized in the Company’s consolidated statements of operations due to changes in the fair value of the warrant (in thousands):

	Years Ended December 31,
	2020		2019		2018
Gain from changes in the fair value of level 3 investments	$	422	$	—	$	—