Net Income per Share

The following table presents the calculation of basic and diluted net income per share (in thousands, except per share information):



	Three Months Ended March 31,
	2019		2018
Net income	$	7,026	$	4,928
Basic:
Weighted-average shares of common stock outstanding	31,376		32,752
Shares used in computing basic net income per share	31,376		32,752
Effect of dilutive securities:
Restricted stock subject to vesting	542		491
Shares issuable for acquisition consideration (1)	296		547
Shares used in computing diluted net income per share	32,214		33,790

Basic net income per share	$	0.22	$	0.15
Diluted net income per share	$	0.22	$	0.15

(1)

For the three months ended March 31, 2019, this represents the shares held in escrow pursuant to: (i) the Asset Purchase Agreement with Zeon Solutions Incorporated and certain related entities (collectively, “Zeon”); (ii) the Asset Purchase Agreement with RAS & Associates, LLC (“RAS”); (iii) the Asset Purchase Agreement with Southport Services Group, LLC (“Southport”); (iv) the Asset Purchase Agreement with Stone Temple Consulting Corporation (“Stone Temple”); and (v) the Agreement and Plan of Merger with Elixiter, Inc. (“Elixiter”), as part of the consideration. For the three months ended March 31, 2018, this represents the shares held in escrow pursuant to: (i) the Asset Purchase Agreement with BioPharm Systems, Inc. (“BioPharm”); (ii) the Asset Purchase Agreement with Zeon; (iii) the Asset Purchase Agreement with RAS; and (iv) the Asset Purchase Agreement with Clarity Consulting, Inc. and Truth Labs, LLC (together, “Clarity”), as part of the consideration.

The number of anti-dilutive securities not included in the calculation of diluted net income per share were as follows (in thousands):



	Three Months Ended March 31,
	2019	2018
Restricted stock subject to vesting	105	120
Convertible senior notes	3,823	—
Warrants related to the issuance of convertible senior notes	3,823	—
Total anti-dilutive securities	7,751	120

See Note 10, Long-term Debt for further information on the convertible senior notes and warrants related to the issuance of convertible notes.

The Company’s Board of Directors has authorized the repurchase of up to $235.0 million of Company common stock through a stock repurchase program with an expiration date of December 31, 2019. The program could be suspended or discontinued at any time, based on market, economic, or business conditions. The timing and amount of repurchase transactions will be determined by management based on its evaluation of market conditions, share price, and other factors. Since the program’s inception on August 11, 2008, the Company has repurchased approximately $210.9 million (15.1 million shares) of outstanding common stock through March 31, 2019.