Equity Plans (Tables)

12 Months Ended

Dec. 31, 2016

Schedule of Activity under Equity Incentive Plans

Activity under the Company’s equity incentive plans is set forth below:


							Options Outstanding
	Options Available for Grant			Options Outstanding			Weighted- Average Exercise Price Per Share		Weighted- Average Remaining Contractual Life (years)		Aggregate Intrinsic Value
											(in thousands)
Balances at December 31, 2013		70,082			284,879		$	1.10		7.92
Additional options authorized		240,425			—
Options granted		(199,519	)		199,519			1.83
Options exercised		—			(2,548	)		1.30
Options forfeited		5,844			(5,844	)		1.13

Balances at December 31, 2014		116,832			476,006			1.40		8.04
Additional options authorized		431,411			—
Options granted		(408,623	)		408,623			1.24
Options exercised		—			(43,852	)		1.30
Options forfeited		7,599			(7,599	)		1.40

Balances at December 31, 2015		147,219			833,178			1.33		8.56
Additional options authorized		1,697,088			—
Options granted		(1,679,979	)		1,679,979			14.24
Options exercised		—			(119,328	)		1.28

Balances at December 31, 2016		164,328			2,393,829		$	10.39		8.79	$	27,820

Options exercisable – December 31, 2016					492,714		$	5.19		7.70	$	8,286

Options vested and expected to vest – December 31, 2016					2,369,135		$	10.37		8.79	$	27,596

Schedule of Stock-based Compensation Expense for Employees and Non-employees for Stock Options and the 2016 ESPP

Total stock-based compensation expense recognized for both employees and non-employees for stock options and the 2016 ESPP was as follows (in thousands):


	Year Ended December 31,
	2016		2015		2014
Research and development	$	1,080	$	39	$	17
General and administrative		1,050		60		25

Total stock-based compensation expense	$	2,130	$	99	$	42

Employee and Director [Member]

Schedule of Grant-date Fair Value of Stock Option Awards Using Black-Scholes Option Pricing Model Assumptions

The fair value of employee and director stock option awards was estimated at the date of grant using a Black-Scholes option-pricing model with the following assumptions:


	Year Ended December 31,
	2016			2015			2014
Expected term (in years)		4.16 – 5.95			5.89			6.08
Expected volatility		62.5 – 64.8	%		59.8	%		64.7	%
Risk-free interest rate		1.27 – 1.79	%		1.57 – 1.58	%		1.89	%
Dividend yield		—			—			—

Non-employees [Member]

Schedule of Grant-date Fair Value of Stock Option Awards Using Black-Scholes Option Pricing Model Assumptions

The fair value of the stock options granted was calculated at each reporting date using the Black-Scholes option-pricing model with the following assumptions:


	Year Ended December 31,
	2016			2015			2014
Expected term (in years)		6.59 –9.97			6.8			9.4
Expected volatility		62.5 – 62.8	%		59.8	%		64.7	%
Risk-free interest rate		1.29 – 1.79	%		1.95	%		2.34	%
Dividend yield		—			—			—

2016 Employee Stock Purchase Plan [Member]

Schedule of Grant-date Fair Value of Stock Option Awards Using Black-Scholes Option Pricing Model Assumptions

The fair value of the rights granted under the 2016 ESPP was calculated using the Black-Scholes option-pricing model with the following assumptions:


	Year Ended
	December 31, 2016
Expected term (in years)		0.60
Expected volatility		52.48	%
Risk-free interest rate		0.45	%
Dividend yield		—