Significant Accounting Policies (Tables)

9 Months Ended

Sep. 30, 2017

Accounting Policies [Abstract]

Summary of Liabilities Fair Value Measurements

The following table summarizes the conclusions reached as of December 31, 2016 (in thousands):

	December 31, 2016		Level 1		Level 2		Level 3
Liabilities:
Series A convertible preferred stock warrant(1)	$	850	$	—	$	—	$	850
	$	850	$	—	$	—	$	850

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(1) In order to determine the fair value of the convertible preferred stock warrant, we used the Black-Scholes option pricing model (“OPM”). Significant inputs for the OPM included an estimate of the fair value of the Series A convertible preferred stock, the remaining contractual life of the warrant, an estimate of the timing of a liquidity event, a risk-free rate of interest and an estimate of our stock volatility using the volatilities of guideline peer companies.

Summary of Changes in Level 3 Instruments Measured at Fair Value On Recurring Basis

The following table presents the changes in our Level 3 instruments measured at fair value on a recurring basis during the nine months ended September 30, 2017 and 2016 (in thousands):

	Nine Months Ended September 30,
	2017			2016
Balance as of January 1	$	850		$	650
Change in fair value of warrant liability	341			200
Reclassification of warrant liability to equity	(1,191		)	—
Balance as of September 30	$	—		$	850