Summary of Significant Accounting Policies (Tables)

6 Months Ended

Jun. 30, 2018

Summary of Significant Accounting Policies

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

	Fair Value Measurements as of June 30, 2018
	Estimated Fair Value		Level 1		Level 2		Level 3
Assets
Cash equivalents:
Money market funds	$	120,031	$	120,031	$	—	$	—
Commercial paper		500		—		500		—
Total cash equivalents		120,531		120,031		500		—
Short-term investments:
Commercial paper	$	997	$	—	$	997		—
Corporate bonds		1,110		—		1,110		—
Total short-term investments		2,107		—		2,107		—
Total assets	$	122,638	$	120,031	$	2,607	$	—

	Fair Value Measurements as of December 31, 2017
	Estimated Fair Value		Level 1		Level 2		Level 3
Assets
Cash equivalents:
Money market funds	$	6,446	$	6,446	$	—	$	—
Commercial paper		1,099		—		1,099		—
Total cash equivalents		7,545		6,446		1,099		—
Short-term investments:
Commercial paper	$	5,384	$	—	$	5,384		—
Corporate bonds		1,804		—		1,804		—
Total short-term investments		7,188		—		7,188		—
Total assets	$	14,733	$	6,446	$	8,287	$	—
Liabilities
Preferred stock warrants	$	157	$	—	$	—	$	157

Schedule of reconciliation of preferred stock warrant liabilities

	Three Months Ended June 30,					Six Months Ended June 30,
	2018			2017		2018			2017
Balance at beginning of period	$	978		$	57	$	157		$	53
Initial fair value of preferred stock warrants issued		—			—		103			4
Reclassified to equity		(855	)		—		(855	)		—
Change in fair value of preferred stock warrants		(123	)		—		595			—
Balance at end of period	$	—		$	57	$	—		$	57