Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2017

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Stock-Based Compensation Expense

Total stock-based compensation expense related to the Company’s equity incentive plans and 2016 ESPP was as follows (in thousands):

	Three Months Ended March 31,
	2017		2016
Research and development	$	110	$	54
General and administrative		291		86
Total stock-based compensation expense	$	401	$	140

Schedule of Estimated Fair Value of Stock Options Granted

The following table summarizes the weighted-average Black-Scholes option pricing model assumptions used to estimate the fair value of stock options granted under the equity incentive plans and the shares purchasable under the 2016 ESPP during the periods presented:

	Three Months Ended March 31,
	2017			2016
Equity Incentive Plans
Expected term		5.99			5.94
Expected volatility		86	%		87	%
Risk-free interest		2.13	%		1.26	%
Dividend yield		0	%		0	%
2016 ESPP
Expected term		0.50			—
Expected volatility		79	%		—
Risk-free interest		0.68	%		—
Dividend yield		0	%		—