Share-Based Payments (Tables)

3 Months Ended

Mar. 31, 2019

Share-Based Payments

Schedule of allocation of share-based compensation expense

	Three Months ended
	March 31,
(in thousands)	2018		2019
Research and development	$	516	$	425
General and administrative		728		1,482
Total	$	1,244	$	1,907

SOP 2015

Share-Based Payments

Summary of information regarding stock option awards

		Weighted
		average
		exercise
		price in $	Aggregate
Stock Option Plan 2015	Options	per share	intrinsic value
Outstanding as of January 1, 2019	2,842,913	8.34
Granted	—	—
Exercised	—	—
Forfeited	(22,664)	9.86
Outstanding as of March 31, 2019	2,820,249	8.33	$	—
Vested and exercisable as of March 31, 2019	1,988,358	8.12	$	—

2017 Share Incentive Plan

Share-Based Payments

Summary of information regarding stock option awards

		Weighted
		average
		exercise
		price in $	Aggregate
2017 Plan	Options	per share	intrinsic value
Outstanding as of January 1, 2019	2,398,425	5.41
Granted	2,211,100	1.90
Exercised	—	—
Forfeited	(78,162)	3.75
Outstanding as of March 31, 2019	4,531,363	3.73	$	1,272
Vested and exercisable as of March 31, 2019	549,309	6.36		—

Summary of assumptions used for valuation of options

Input parameters
Range of expected volatility	61.4% – 61.6%
Expected term of options (in years)	6.1
Range of risk-free interest rate	2.47% – 2.58%
Dividend yield	—

2019 Inducement Plan

Share-Based Payments

Summary of information regarding stock option awards

		Weighted
		average
		exercise
		price in $	Aggregate
2019 Inducement Plan	Options	per share	intrinsic value
Outstanding as of January 1, 2019	—	—
Granted	41,150	2.44
Exercised	—	—
Forfeited	—	—
Outstanding as of March 31, 2019	41,150	2.44	$	—
Vested and exercisable as of March 31, 2019	—	—		—

Summary of assumptions used for valuation of options

Input parameters
Expected volatility	61.6%
Expected term of options (in years)	6.1
Risk-free interest rate	2.27%
Dividend yield	—

Inducement Awards Outside of the 2019 Inducement Plan

Share-Based Payments

Summary of assumptions used for valuation of options

Input parameters
Expected volatility	59.8%
Expected term of options (in years)	6.1
Range of risk-free interest rate	2.9%
Dividend yield	—