Equity

3 Months Ended

Mar. 31, 2020

Equity

Equity

12. Equity

The changes in shareholders’ equity for three months ended March 31, 2020 were as follows:

				Additional				Total
	Common Stock			Paid- In		Accumulated		Shareholders’
	Shares		Amount	Capital		Deficit		Equity (Deficit)
Balance, December 31, 2019	33,678,840	$	34	$	447,297	$	(359,899)	$	87,432
Exercise of common stock options	455,573		—		4,454		—		4,454
Issuance for employee stock purchase plan	39,411		—		357		—		357
Vesting of restricted stock units ("RSUs")	195,280		—		—		—		—
Shares withheld for employee taxes upon vesting of RSUs	(63,064)		—		(1,358)		—		(1,358)
Stock-based compensation	—		—		4,951		—		4,951
Equity component of 2020 Convertible Notes, net of issuance costs of $1,773	—		—		44,777		—		44,777
Net income	—		—		—		450		450
Balance, March 31, 2020	34,306,040	$	34	$	500,478	$	(359,449)	$	141,063

The changes in shareholders’ equity for three months ended March 31, 2019 were as follows:

				Additional				Total
	Common Stock			Paid- In		Accumulated		Shareholders’
	Shares		Amount	Capital		Deficit		Equity (Deficit)
Balance, December 31, 2018	33,265,629	$	33	$	428,729	$	(337,177)	$	91,585
Exercise of common stock options	18,693		—		246		—		246
Issuance for employee stock purchase plan	32,826		—		444		—		444
Vesting of RSUs	101,483		—		—		—		—
Shares withheld for employee taxes upon vesting of RSUs	(33,503)		—		(488)		—		(488)
Stock-based compensation	—		—		4,263		—		4,263
Net loss	—		—		—		(9,700)		(9,700)
Balance, March 31, 2019	33,385,128	$	33	$	433,194	$	(346,877)	$	86,350

Warrants

As of March 31, 2020, the warrant issued to Assertio in November 2018 was the Company’s only outstanding warrant. In connection with the Third Amendment to the Nucynta Commercialization Agreement, the Company issued a warrant to Assertio to purchase 1,041,667 shares of common stock of the Company at an exercise price of $19.20 per share. The terms of the warrant are fixed, with the exception of customary adjustments for changes in the Company’s capitalization. The warrant may only be settled with the issuance of shares of common stock upon exercise and will expire in November 2022. The Company has recorded the relative fair value of the warrant as a component of equity interest issued by the Company as consideration transferred in the cost accumulation model for the asset acquisition. The Company estimated the fair value of the warrant on the date of issuance to be approximately $8,043 using the Black-Scholes option-pricing model. The Company concluded that the warrant met the definition of an equity instrument and was recorded as a component of additional paid-in capital in the Company’s Condensed Consolidated Balance Sheet as of the issuance date.