|6 Months Ended|
Jun. 30, 2018
|Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]|
In January 2018, we completed an underwritten public offering of 7,675,072 shares of common stock at an offering price of $18.25 per share and received net proceeds of $131.4 million, after deducting underwriting discounts and commissions and offering expenses payable by us. Further, in March 2018, we completed an underwritten public offering of 4,928,571 shares of common stock at an offering price of $35.00 per share and received net proceeds of $161.9 million, after deducting underwriting discounts and commissions and offering expenses payable by us.
In March 2017, we entered into a sales agreement (the “ATM Facility”) with Cowen and Company, LLC (“Cowen”) for the sale, in our sole discretion, of shares of our common stock, having an aggregate offering price of up to $75.0 million through Cowen, as our sales agent. We pay Cowen a commission of up to 3.0% of the gross sales proceeds of any common stock sold under the ATM Facility. The issuance and sale of these shares by us pursuant to the ATM Facility are deemed “at the market” offerings and are available under the Securities Act of 1933, as amended.
During the three and six months ended June 30, 2018, we sold an aggregate of 1,007,806 shares of common stock under the ATM facility, at an average price of approximately $48.52 per share, for gross proceeds of $48.9 million and net proceeds of $47.6 million, after deducting commissions and other offering expenses. As of June 30, 2018, $6.1 million of common stock remained available to be sold under this facility, subject to certain conditions as specified in the agreement.
Equity Incentive Plans
Under the terms of the 2014 Equity Incentive Plan (“2014 EIP”), we may grant options, restricted stock awards (“RSAs”) and RSUs to employees, directors, consultants and other service providers. As of June 30, 2018, a total of 10,851,962 shares of common stock were reserved for issuance under the 2014 EIP, of which 3,958,128 shares were available for future grant and 6,893,834 shares were subject to outstanding options and RSUs.
In February 2018, we adopted the 2018 Inducement Plan (“2018 IP”), under which we may grant options, stock appreciation rights, RSAs and RSUs to new employees. As of June 30, 2018, 1,250,000 shares of common stock were reserved for issuance under the 2018 IP, of which 882,500 shares were available for future grant and 367,500 shares were subject to outstanding options and RSUs.
Restricted Stock Units
The following is a summary of RSU activity under our 2014 EIP and 2018 IP:
The fair value of RSUs is determined as the closing stock price on the date of grant. The weighted average grant date fair value of RSUs granted was $36.69 and $15.78 for the six months ended June 30, 2018 and 2017, respectively. As of June 30, 2018, there was $37.5 million of unrecognized stock-based compensation expense related to RSUs that is expected to be recognized over a weighted average period of 2.8 years. The aggregate intrinsic value of the RSUs outstanding as of June 30, 2018 was $66.2 million.
Under our RSU net settlement procedures, for most of our employees, we withhold shares at settlement to cover the minimum payroll withholding tax obligations. During the six months ended June 30, 2018, we settled 380,034 RSUs, of which 233,836 RSUs were net settled by withholding 87,954 shares. The value of the RSUs withheld was $3.4 million, based on the closing price of our common stock on the settlement date. During the six months ended June 30, 2017, we settled 253,399 RSUs, of which 49,691 RSUs were net settled by withholding 21,201 shares. The value of the RSUs withheld was $0.3 million, based on the closing price of our common stock on the settlement date. The value of RSUs withheld in each period was remitted to the appropriate taxing authorities and has been reflected as a financing activity in our condensed consolidated statements of cash flows.
The following is a summary of stock option activity under our 2014 EIP and 2018 IP. The table below also includes 275,000 stock options which were issued in 2017 outside of these plans:
Aggregate intrinsic value represents the difference between the closing stock price of our common stock on June 30, 2018 and the exercise price of outstanding, in-the-money options. As of June 30, 2018, there was $52.8 million of unrecognized stock-based compensation expense related to stock options that is expected to be recognized over a weighted average period of 3.0 years.
Options for 622,982 shares of our common stock were exercised during the six months ended June 30, 2018, with an intrinsic value of $11.3 million. No options were exercised during the six months ended June 30, 2017. As we believe it is more likely than not that no stock option related tax benefits will be realized, we do not record any net tax benefits related to exercised options.
The fair value of each option issued was estimated at the date of grant using the Black-Scholes valuation model. The following table summarizes the weighted-average assumptions used as inputs to the Black-Scholes model, and resulting weighted-average grant date fair values of stock options granted to employees during the periods indicated:
The estimated fair value of stock options that vested in the six months ended June 30, 2018 and 2017 was $8.2 million and $7.4 million, respectively.
Employee Stock Purchase Plan
As of June 30, 2018, there were 943,338 shares available for purchase under the 2014 Employee Stock Purchase Plan (“2014 ESPP”). The Company recorded $0.2 million and $0.1 million of expense related to the 2014 ESPP in the six months ended June 30, 2018 and 2017, respectively. 77,100 and 43,962 shares were purchased under the 2014 ESPP during the six months ended June 30, 2018 and 2017, respectively.
The following shares of common stock were reserved for future issuance as of June 30, 2018:
Stock-based Compensation Expense
Total stock-based compensation expense related to all employee and non-employee stock awards was as follows:
The entire disclosure for shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Includes, but is not limited to, balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings, accumulated balance for each classification of other comprehensive income and amount of comprehensive income.
Reference 1: http://www.xbrl.org/2003/role/presentationRef