Stockholders' Equity (Deficit) (Tables)

3 Months Ended

Mar. 31, 2018

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Schedule of Share-based Compensation, Allocation of Recognized Period Costs

Total stock-based compensation expense for employees and non-employees recognized in the statements of operations was as follows (in thousands):

	Three Months Ended March 31,
	2018		2017
	(unaudited)
Research and development	$	426	$	177
General and administrative	396		139
Total stock-based compensation expense	$	822	$	316

Schedule of Stock Option Activity

The table below summarizes stock option and restricted award activity under the 2011 and 2018 Plan:

	Number of Shares Outstanding		Weighted-Average Exercise Price		Weighted- Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value (in thousands)
Balances at December 31, 2017	2,506,926		$	3.50	8.79	$	24,033
Forfeited	(6,772	)	7.01
Granted	5,600		31.58
Balances at March 31, 2018	2,505,754		$	3.57	8.58	$	85,225