Share-Based Payments (Tables)

3 Months Ended

Mar. 31, 2019

Summary of Company's Stock Option Activity

The following table summarizes the Company’s stock option activity during the three months ended March 31, 2019:

				Weighted		Aggregate
	Number of			Average		Intrinsic Value
	Stock Options			Exercise Price		(in thousands)
Outstanding as of December 31, 2018		3,308,049		$	7.14	$	8,308
Granted		640,158			6.93		—
Forfeited/Cancelled		(54,108	)		10.16		—
Outstanding as of March 31, 2019		3,894,099		$	7.06	$	3,890
Exercisable as of March 31, 2019		1,960,235		$	2.82	$	3,890

Summary of Stock-Based Compensation Expense is Classified in Condensed Consolidated Statements of Operations and Comprehensive Loss

Stock-based compensation expense is classified in the Company’s condensed consolidated statements of operations and comprehensive income (loss) as follows (amounts in thousands):

	Three Months Ended March 31,
	2019		2018
Research and development	$	195	$	99
Cost of sales		3		—
Selling, general and administrative		637		288
Total	$	835	$	387

Employee and Director Stock Options

Summary of Stock Options Outstanding and Exercisable

The following table summarizes stock options outstanding and exercisable by employees and directors as of March 31, 2019: 

			Options
			Outstanding
			Remaining								Number of
Number of			Contractual Life		Exercise		Fair Value		Grant Date		Options
Options Outstanding		Expiration Date	(In Years)		Price		Post Modification (1)		Fair Value		Exercisable
	360,000	June 18, 2019		0.22	$	2.77	$	6.62	$	—		360,000
	80,000	June 18, 2019		0.22	$	2.77	$	6.62	$	—		80,000
	20,000	December 8, 2019		0.69	$	12.72	$	2.18	$	—		20,000
	80,000	December 8, 2019		0.69	$	12.72	$	2.18	$	—		80,000
	20,000	March 16, 2020		0.96	$	12.52	$	2.43	$	—		20,000
	150,000	October 21, 2020		1.56	$	3.20	$	6.57	$	—		150,000
	20,000	December 31, 2020		1.75	$	4.48	$	5.86	$	—		20,000
	595,000	July 13, 2020		1.29	$	5.35	$	5.18	$	—		595,000
	20,000	August 8, 2020		1.36	$	4.98	$	5.42	$	—		20,000
	617,000	April 17, 2027		8.04	$	8.13	$	7.54	$	—		154,250
	6,146	May 18, 2027		8.13	$	7.35	$	4.75	$	—		4,610
	10,000	May 18, 2027		8.13	$	7.35	$	7.65	$	—		2,500
	30,000	August 8, 2027		8.35	$	10.38	$	7.38	$	—		7,500
	20,000	April 9, 2028		9.02	$	9.03	$	8.01	$	—		—
	337,500	May 15, 2028		9.12	$	10.99	$	7.89	$	—		121,875
	150,000	July 9, 2028		9.27	$	9.69	$	—	$	6.83		—
	73,295	August 22, 2028		9.39	$	10.23	$	—	$	7.21		—
	11,500	September 4, 2028		9.43	$	10.19	$	—	$	7.19		—
	50,000	September 10, 2028		9.44	$	10.34	$	—	$	7.30		—
	50,000	September 24, 2028		9.48	$	9.71	$	—	$	6.79		—
	1,500	October 8, 2028		9.52	$	8.25	$	—	$	5.84		—
	75,000	October 15, 2028		9.54	$	8.75	$	—	$	6.19		—
	50,000	October 22, 2028		9.56	$	10.16	$	—	$	7.20		—
	10,000	October 29, 2028		9.58	$	9.71	$	—	$	6.87		—
	20,000	November 19, 2028		9.63	$	8.00	$	—	$	5.66		—
	20,000	December 3, 2028		9.67	$	8.66	$	—	$	6.13		—
	15,000	December 17, 2028		9.71	$	9.42	$	—	$	6.66		—
	10,000	January 7, 2029		9.77	$	9.10	$	—	$	6.30		—
	50,000	January 14, 2029		9.79	$	8.19	$	—	$	5.67		—
	9,000	January 22, 2029		9.81	$	7.65	$	—	$	5.30		—
	7,500	February 4, 2029		9.84	$	7.26	$	—	$	5.03		—
	3,100	March 18, 2029		9.96	$	6.85	$	—	$	4.73		—
	560,558	March 28, 2029		9.99	$	6.76	$	—	$	4.62		—
	3,532,099											1,635,735
(1) Reflects fair value of modified stock options on August 8, 2018.

Estimation Using Black-Scholes Option Pricing Model With Following Weighted Average Assumptions

The fair value of employee and director stock options for the three months ended March 31, 2019 had a weighted average grant date fair value of $4.71 per option and they were estimated using the Black-Scholes option pricing model using the following weighted average assumptions:

	March 31, 2019
Stock price	$	6.93
Exercise price	$	6.93
Expected term	6.09 years
Expected volatility		76.90	%
Risk-free interest rate		2.28	%
Dividend rate		0.00	%

Non-employee Stock Options

Summary of Stock Options Outstanding and Exercisable

As of March 31, 2019 and December 31, 2018, all non-employee stock options are accounted for as equity instruments. The following table summarizes stock options outstanding and exercisable by non-employees as of March 31, 2019:

			Options
			Outstanding
			Remaining								Number of
Number of			Contractual Life		Exercise		Fair Value		Grant Date		Options
Options Outstanding		Expiration Date	(In Years)		Price		Post Modification 1		Fair Value		Exercisable
	80,000	June 18, 2019		0.22	$	2.77	$	6.62				80,000
	30,000	December 8, 2019		0.69	$	12.72	$	2.18				30,000
	72,000	October 3, 2020		1.51	$	5.15	$	5.35				72,000
	110,000	October 28, 2020		1.58	$	3.18	$	6.59				110,000
	20,000	May 18, 2027		8.13	$	7.35	$	7.65				5,000
	15,000	August 8, 2027		8.35	$	10.38	$	7.38				3,750
	15,000	November 6, 2027		8.60	$	16.20	$	6.98				3,750
	15,000	August 22, 2028		9.39	$	10.23			$	8.87		15,000
	357,000											319,500
(1) Reflects fair value of modified stock options on August 8, 2018.