Investments and Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2019

Fair Value Disclosures [Abstract]

Schedule of Cash, Cash Equivalents, and Marketable Securities

Our total cash, cash equivalents and marketable securities consisted of the following:

	As of December 31,
	2019		2018
	(in thousands)
Cash and cash equivalents:
Cash	$	11,623	$	32,546
Money market funds	2,020		2,419
U.S. Treasury securities	—		1,998
Commercial paper	2,499		—
Total cash and cash equivalents	$	16,142	$	36,963
Marketable securities:
Corporate notes and bonds	$	17,470	$	12,852
Commercial paper	5,481		20,086
U.S. Treasury securities	78,160		5,932
Asset-backed securities	13,856		7,809
Total marketable securities	$	114,967	$	46,679

Schedule of Available-For-Sale Investments

The following table summarizes adjusted cost, gross unrealized gains and losses, and fair value related to available-for-sale securities classified as marketable securities on the accompanying Consolidated Balance Sheets as of December 31, 2019 and December 31, 2018:

	As of December 31, 2019
	Amortized Cost		Gross Unrealized Gain		Gross Unrealized Loss			Fair Value
	(in thousands)
Corporate notes and bonds	$	17,462	$	9	$	(1	)	$	17,470
Commercial paper	5,481		—		—			5,481
U.S. Treasury securities	78,075		85		—			78,160
Asset-backed securities	13,852		4		—			13,856
Total available-for-sale investments	$	114,870	$	98	$	(1	)	$	114,967
	As of December 31, 2018
	Amortized Cost		Gross Unrealized Gain		Gross Unrealized Loss			Fair Value
	(in thousands)
Corporate notes and bonds	$	12,867	$	—	$	(15	)	$	12,852
Commercial paper	20,086		—		—			20,086
U.S. Treasury securities	5,933		—		(1		)	5,932
Asset-backed securities	7,817		—		(8		)	7,809
Total available-for-sale investments	$	46,703	$	—	$	(24	)	$	46,679

Financial Assets and Liabilities Measured and Recorded at Fair Value on a Recurring Basis

Financial assets and liabilities measured and recorded at fair value on a recurring basis consisted of the following types of instruments:

	As of December 31, 2019
	Level 1		Level 2		Level 3		Total
	(in thousands)
Cash equivalents:
Money market funds	$	2,020	$	—	$	—	$	2,020
Commercial paper			2,499		—		2,499
Total cash equivalents	2,020		2,499		—		4,519
Marketable securities:
Corporate notes and bonds	—		17,470		—		17,470
Commercial paper	—		5,481		—		5,481
U.S. Treasury securities	—		78,160		—		78,160
Asset-backed securities	—		13,856		—		13,856
Total marketable securities	—		114,967		—		114,967
Restricted cash:
Money market funds	70,087		—		—		70,087
Total restricted cash	70,087		—		—		70,087
Total financial assets	$	72,107	$	117,466	$	—	$	189,573

	As of December 31, 2018
	Level 1		Level 2		Level 3		Total
	(in thousands)
Cash equivalents:
Money market funds	$	2,419	$	—	$	—	$	2,419
U.S. Treasury securities	—		1,998		—		1,998
Total cash equivalents	2,419		1,998		—		4,417
Marketable securities:
Corporate notes and bonds	—		12,852		—		12,852
Commercial paper	—		20,086		—		20,086
U.S. Treasury securities	—		5,932		—		5,932
Asset-backed securities	—		7,809		—		7,809
Total marketable securities	—		46,679		—		46,679
Total financial assets	$	2,419	$	48,677	$	—	$	51,096
Convertible preferred stock warrant liabilities	$	—	$	—	$	3,261	$	3,261
Total financial liabilities	$	—	$	—	$	3,261	$	3,261

Summary of the Changes in the Fair Value of Level 3 Liabilities

The following table sets forth a summary of the changes in the fair value of our Level 3 financial liabilities:

	As of December 31, 2019
	(in thousands)
Fair value as of December 31, 2018	$	3,261
Change in fair value of Level 3 financial liabilities	2,404
Conversion of convertible preferred stock warrants into Class B common stock warrants	(5,665		)
Fair value as of December 31, 2019	$	—