Stockholders Deficit (Tables)

3 Months Ended

Mar. 31, 2019

A summary of the Company’s stock option activity for the three months ended March 31, 2019 is as follows:

	Number of Shares			Weighted- Average Exercise Price Per Share		Weighted- Average Remaining Contractual Life (Years)		Aggregate Intrinsic Value
Balance at December 31, 2018		2,047,237		$	3.07		7.6	$	366,007
Granted		—			—
Exercised		(21,871	)		2.36			$	8,306
Forfeited		(36,797	)		3.15
Expired/Cancelled		(10,782	)		4.81
Balance at March 31, 2019		1,977,787		$	3.07		7.5	$	320,766
Exercisable at March 31, 2019		1,288,938		$	2.93		6.6	$	307,101

Summary of Restricted Stock Unit (“RSU”) Plans Activity

A summary of restricted stock unit (“RSU”) activity for the three months ended March 31, 2019 is as follows:

	Number of Shares			Weighted- Average Grant Date Fair Value Per Share
Balance at December 31, 2018		227,707		$	3.39
Granted		15,000			2.31
Released		(13,126	)		3.40
Balance at March 31, 2019		229,581		$	3.32
Vested and unissued at March 31, 2019		15,001		$	3.26

Summary of Stock-Based Compensation

Stock-based compensation expense recorded in the accompanying condensed consolidated statements of operations for the three months ended March 31, 2019 and 2018 was as follows:

	Three Months Ended March 31,
	2019		2018
Selling, general and administrative	$	181,981	$	1,101,992
Research and development		48,450		30,909
Cost of product and product-related services revenue		10,815		10,557
	$	241,246	$	1,143,458