Share-based Compensation (Tables)

6 Months Ended

Jun. 30, 2020

Share-based Payment Arrangement [Abstract]

Schedule of Share-based Compensation Expense

During the periods presented, the Company recorded the following share-based compensation expense for stock options and restricted stock awards:

	Three Months Ended June 30,				Six Months Ended June 30,
	2020		2019		2020		2019
	(in thousands)
Sales, general and administrative	$	1,139	$	1,413	$	2,446	$	2,681
Research and development	418		481		740		1,049
Total	$	1,557	$	1,894	$	3,186	$	3,730

Schedule of Stock Options

Stock Options

	Number of Options Outstanding	Weighted-Average Exercise Price		Weighted-Average Remaining Contractual Term (in years)	Aggregate Intrinsic Value (in thousands)
Balances at December 31, 2019	1,837,576	$	14.54	8.06	$	24,122
Granted (weighted-average fair value of $10.64 per share)	367,265	19.11
Exercised	(62,457)	5.99
Forfeited/canceled	(97,750)	15.70
Balances at June 30, 2020	2,044,634	$	15.57	8.04	$	10,046

Schedule of Employee Stock Options Valuation Assumptions

The fair value of stock options granted to employees was estimated using the following assumptions:

	Six Months Ended June 30,
	2020	2019
Volatility	55% - 60%	56%
Risk-free interest rate	0.4% - 1.5%	1.9% - 2.6%
Term (in years)	6.25	6.25
Dividend yield	—	—

The fair value of stock options granted to consultants was estimated using the following assumptions during the following periods presented:

	Six Months Ended June 30,
	2020	2019
Volatility	56% - 60%	57%
Risk-free interest rate	0.6% - 1.6%	2.1%
Term (in years)	10	10
Dividend yield	—	—

Schedule of Restricted Stock

The following table represents RSA activity for fiscal 2020:

	Restricted Stock Awards	Weighted- Average Grant Date Fair Value
Outstanding unvested at December 31, 2019	128,682	$	11.81
Granted	—	—
Vested	(16,864)	12.53
Forfeited/canceled	(9,148)	9.55
Outstanding unvested at June 30, 2020	102,670	$	11.90