Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2018

Stock-Based Compensation

Schedule of stock option activity

		Options Outstanding
	Shares		Weighted-
	Available	Number of	Average
	for Grant	Shares	Exercise Price
Balance — December 31, 2016	214,758	455,605	$	8.75
Additional shares reserved	77,908	—	$	—
Options granted	(158,918)	158,918	$	11.38
Options cancelled	11,232	(11,232)	$	4.64
Balance — December 31, 2017	144,980	603,291	$	9.52
Additional shares reserved	77,908	—	$	—
Options exercised	—	(974)	$	9.63
Options granted	(291,100)	291,100	$	17.21
Options cancelled	68,212	(68,212)	$	10.52
Balance — December 31, 2018	—	825,205	$	12.15

Schedule of options outstanding and exercisable by exercise price

Options Outstanding and Exercisable at December 31, 2018
			Weighted Average
			Remaining
Exercise		Number	Contractual Life	Total Shares	Weighted Average
Price		Outstanding	(in years)	Exercisable	Exercise Price
$	2.89	183,840	5.9	182,151	$	2.89
$	8.50	47,883	9.9	125	$	8.50
$	9.63	72,340	8.5	31,238	$	9.63
$	12.77	23,175	9.7	2,095	$	12.77
$	12.96	58,161	7.0	54,786	$	12.93
$	13.16	181,915	7.8	178,602	$	13.16
$	17.01	154,711	9.0	42,284	$	17.01
$	17.20	103,180	9.3	27,927	$	17.20
$	11.24	825,205	8.2	519,208	$	9.85

Options

Stock-Based Compensation

Schedule of fair value of the options granted estimated using assumptions

	Year Ended December 31,
	2018	2017
Expected term (in years)	6.25	6.25
Expected volatility	77% - 79%	78% - 80%
Risk-free interest-rate	2.22% - 2.99%	1.83% - 2.22%
Dividend yield	0%	0%

Options | Number of shares excess granted under the 2014 Plan

Stock-Based Compensation

Schedule of fair value of the options granted estimated using assumptions

	Year Ended December 31,
	2018
Expected term (in years)	6.25
Expected volatility	77% - 79%
Risk-free interest-rate	2.22% - 2.99%
Dividend yield	0%

Options | Consultants

Stock-Based Compensation

Schedule of fair value of the options granted estimated using assumptions

	Year Ended December 31,
	2018	2017
Expected term (in years)	9.7	9.2 - 10.0
Expected volatility	84%	76% - 85%
Risk-free interest-rate	3.01%	2.20% - 2.40%
Dividend yield	0%	0%