10. Convertible Senior Notes

The carrying value of the Company’s convertible senior notes is as follows (in thousands):


	June 30, 2018			December 31, 2017
2.125% Convertible Senior Notes due 2021:
Principal amount	$	114,989		$	115,000
Unamortized debt discount		(11,617	)		(13,395	)
Unamortized debt issuance costs		(2,043	)		(2,355	)

Total convertible senior notes	$	101,329		$	99,250
Less: Current portion		(101,329	)		—

Total convertible senior notes, long term	$	—		$	99,250

On May 24, 2016, the Company issued $115 million aggregate principal amount of its Notes. The net proceeds from the sale of the Notes, after deducting the underwriting discounts and commissions and other related offering expenses, were approximately $111.1 million. The Notes bear interest at the rate of 2.125% per annum, payable semiannually in arrears on June 1 and December 1 of each year, beginning December 1, 2016.

The Notes will mature on June 1, 2021, unless earlier repurchased, redeemed or converted in accordance with their terms. Prior to March 1, 2021, the Notes will be convertible at the option of holders of the Notes only upon satisfaction of certain conditions and during certain periods, and thereafter, the notes will be convertible at any time until the close of business on the second scheduled trading day immediately preceding the maturity date. Upon conversion, holders of the Notes will receive shares of the Company’s common stock, cash or a combination thereof, at the Company’s election. It is the Company’s current intent and policy to settle all conversions through combination settlement, which involves satisfying the principal amount outstanding with cash and any note conversion value over the principal amount in shares of the Company’s common stock.

Notes with a par value of $11,000 were submitted for conversion in the fourth quarter of 2017, and this conversion was settled in the first quarter of 2018. The conversion resulted in the issuance of a nominal amount of shares of the Company’s common stock, and the Company recorded a loss of $1,000 on the conversion of these Notes.

During the second quarter of 2018, the closing price of the Company’s common stock exceeded 130% of the conversion price of the Notes for more than 20 trading days of the last 30 consecutive trading days of the quarter. As a result, the Notes are convertible at the option of the holders of the Notes during the third quarter of 2018. The Company reclassified the carrying value of the Notes from long term liabilities to current liabilities on the Company’s consolidated balance sheet as of June 30, 2018. As of June 30, 2018, the if-converted value of the Notes exceeded the aggregate principal amount by approximately $63.8 million. As of the date of this filing, no Notes have been converted by the holders of such Notes in the third quarter of 2018. In the event the closing price conditions are met in the third quarter of 2018 or a future fiscal quarter, the Notes will be convertible at a holder’s option during the immediately following fiscal quarter.

The conversion rate for the Notes will initially be 31.1813 shares of the Company’s common stock per $1,000 principal amount of Notes, which is equivalent to an initial conversion price of approximately $32.07 per common share, and is subject to adjustment under the terms of the Notes. Holders of the Notes may require the Company to repurchase their Notes upon the occurrence of a fundamental change prior to maturity for cash at a repurchase price equal to 100% of the principal amount of the Notes to be repurchased plus accrued and unpaid interest, if any, to, but excluding, the repurchase date.

The Company will not have the right to redeem the Notes prior to June 5, 2019, but may redeem the Notes, at its option, in whole or in part, on any business day on or after June 5, 2019 and prior to the maturity date if the last reported sale price of the Company’s common stock has been at least 130% of the conversion price then in effect for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading day period ending on, and including, the trading day immediately preceding the date on which the Company provides written notice of redemption. The redemption price will be equal to 100% of the principal amount of the principal amount of Notes to be redeemed plus accrued and unpaid interest to, but excluding, the redemption date.

The Notes contain customary terms and events of default. If an event of default (other than certain events of bankruptcy, insolvency or reorganization involving the Company) occurs and is continuing, the holders of at least 25% in aggregate principal amount of the outstanding Notes may declare 100% of the principal of, and any accrued and unpaid interest on, all of the Notes to be due and payable. Upon the occurrence of certain events of bankruptcy, insolvency or reorganization involving the Company, 100% of the principal of and accrued and unpaid interest, if any, on all of the Notes will become due and payable automatically. Notwithstanding the foregoing, the Notes provide that, to the extent the Company elects and for up to 270 days, the sole remedy for an event of default relating to certain failures by the Company to comply with certain reporting covenants consist exclusively of the right to receive additional interest on the Notes. The Company is not aware of any events of default, current events or market conditions that would allow holders to call or convert the Notes as of June 30, 2018.

The cash conversion feature of the Notes required bifurcation from the Notes and was initially accounted for as an equity instrument classified to stockholders’ equity, as the conversion feature was determined to be clearly and closely related to the Company’s stock. Based on market data available for publicly traded, senior, unsecured corporate bonds issued by companies in the same industry and asset base and with similar maturity, the Company estimated the implied interest rate, assuming no conversion option. Assumptions used in the estimate represent what market participants would use in pricing the liability component, including market interest rates, credit standing, and yield curves, all of which are defined as Level 2 observable inputs. The estimated implied interest rate was applied to the Notes, which resulted in a fair value of the liability component of $96,289,000 upon issuance, calculated as the present value of implied future payments based on the $115 million aggregate principal amount. The equity component of the Notes was recognized as a debt discount, recorded in additional paid-in capital, and represents the difference between the aggregate principal of the Notes and the fair value of the Notes without conversion option on their issuance date. The debt discount is amortized to interest expense using the effective interest method over five years, or the life of the Notes. The Company assesses the equity classification of the cash conversion feature quarterly, and it is not re-measured as long as it continues to meet the conditions for equity classification.

Interest expense recognized on the Notes during the three-month period ended June 30, 2018 includes $611,000, $896,000 and $157,000 for the contractual coupon interest, the accretion of the debt discount and the amortization of the debt issuance costs, respectively. Interest expense recognized on the Notes during the six-month period ended June 30, 2018 includes $1,222,000, $1,777,000 and $312,000 for the contractual coupon interest, the accretion of the debt discount and the amortization of the debt issuance costs, respectively. The effective interest rate on the Notes is 6.6%, which includes the interest on the Notes, amortization of the debt discount and debt issuance costs. As of June 30, 2018, the carrying value of the Notes was approximately $101.3 million and the fair value of the principal was approximately $178.8 million. The fair value of the Notes was determined based on the most recent trade activity of the Notes as of June 30, 2018.