Credit Facility and Convertible Debentures	3 Months Ended
Mar. 31, 2018
Debt Disclosure [Abstract]
Credit Facility and Convertible Debentures	Convertible Debentures Credit Facility In May 2017, the Company entered into a $75.0 million secured, revolving credit facility (“Credit Facility”) with HPS Investment Partners, LLC (“Lender”). At closing, the Company borrowed $50.0 million, which resulted in net proceeds of $44.3 million after closing fees to the Lender and other third parties. The Credit Facility has a three-year term with a scheduled maturity of May 11, 2020 and bears interest at a rate of either: (A) LIBOR plus 8.5% (subject to a LIBOR floor of 1%), payable on the last day of the one, two or three month interest period applicable to the LIBOR rate advance, or (B) 7.5% plus the greater of: 2%; the Federal Funds Rate plus 0.5%; LIBOR plus 1%; or the U.S. Prime Rate, payable monthly in arrears. The Credit Facility is not amortized and interest payable under the Credit Facility will reflect at least $50 million as being drawn and outstanding at all times during the term. The Credit Facility also includes an unused line fee equal to 0.75% per annum of the average unused portion of the Credit Facility and a loan service fee, both paid quarterly. The Credit Facility is secured by all of the Company's assets in accordance with the terms of the Credit Facility. The Credit Facility requires the Company to maintain (i) a liquidity threshold of at least $20 million of unrestricted cash; (ii) a tangible net worth, plus unrestricted cash of at least 1.75x the amount then outstanding under the Credit Facility; (iii) a minimum aggregate appraised value of the Company’s ownership interests in its partner companies, plus unrestricted cash in excess of the liquidity threshold of at least $350 million; and (iv) certain diversification requirements and concentration limits with respect to the Company’s capital deployments to its partner companies. Subject to customary exclusions, the Lender has the right to have one observer representative attend meetings of the Company's Board of Directors. The Credit Facility provides for customary events of default which include (subject in certain cases to customary grace and cure periods), among others, nonpayment of principal or interest; non-compliance with debt covenants; defaults in, or failure to pay, certain other indebtedness; the rendering of judgments to pay certain amounts of money; and certain events of bankruptcy or insolvency. Generally, if an event of default occurs and is not cured within the time periods specified (if any), the Lender may declare the outstanding amount under the Credit Facility to be immediately due and payable. At March 31, 2018, the principal amount outstanding under the Credit Facility was $50.0 million, the unamortized discount and debt issuance costs were $4.3 million and the net carrying value of the credit facility was $45.7 million. The Company is amortizing the excess of the principal amount of the Credit Facility over its carrying value over the three-year term as additional interest expense using the effective interest method. For the three months ended March 31, 2018, the Company recorded $1.8 million of interest expense and made cash interest payments of $1.3 million under the Credit Facility. The effective interest rate on the Credit Facility is 15.0%. Convertible Debentures In November 2012, the Company issued $55.0 million principal amount of its 5.25% convertible senior debentures due on May 15, 2018 (the “2018 Debentures”). Interest on the 2018 Debentures is payable semi-annually. In July and June 2017, the Company repurchased on the open market, and retired, an aggregate of $14.0 million face value of the 2018 Debentures at a cost of $14.5 million, including transaction fees. At March 31, 2018, the Company had $41.0 million of outstanding 2018 Debentures. The 2018 Debentures may be settled in cash or partially in cash upon conversion. Accordingly, the Company separately accounts for the liability and equity components of the 2018 Debentures. The carrying amount of the liability component was determined at the transaction date by measuring the fair value of a similar liability that does not have an associated equity component. The carrying amount of the equity component represented by the embedded conversion option was determined by deducting the fair value of the liability component from the initial proceeds of the 2018 Debentures as a whole. At March 31, 2018, the carrying amount of the equity component was $5.6 million, the principal amount of the liability component was $41.0 million, the unamortized discount and debt issuance costs were $0.2 million and the net carrying value of the liability component was $40.8 million. The Company is amortizing the excess of the face value of the 2018 Debentures over their carrying value over their term as additional interest expense using the effective interest method. The Company recorded interest expense of $0.9 million and $1.1 million for the three months ended March 31, 2018 and 2017, respectively. The cash interest paid was zero for the three months ended March 31, 2018 and 2017. The effective interest rate on the 2018 Debentures is 8.7%. At March 31, 2018, the fair value of the $41.0 million outstanding 2018 Debentures was approximately $41.3 million, based on the midpoint of the bid and ask prices as of such date. The Company anticipates refinancing the outstanding 2018 Debentures by the maturity date of May 15, 2018.

Convertible Debentures

Credit Facility

In May 2017, the Company entered into a $75.0 million secured, revolving credit facility (“Credit Facility”) with HPS Investment Partners, LLC (“Lender”). At closing, the Company borrowed $50.0 million, which resulted in net proceeds of $44.3 million after closing fees to the Lender and other third parties. The Credit Facility has a three-year term with a scheduled maturity of May 11, 2020 and bears interest at a rate of either: (A) LIBOR plus 8.5% (subject to a LIBOR floor of 1%), payable on the last day of the one, two or three month interest period applicable to the LIBOR rate advance, or (B) 7.5% plus the greater of: 2%; the Federal Funds Rate plus 0.5%; LIBOR plus 1%; or the U.S. Prime Rate, payable monthly in arrears. The Credit Facility is not amortized and interest payable under the Credit Facility will reflect at least $50 million as being drawn and outstanding at all times during the term. The Credit Facility also includes an unused line fee equal to 0.75% per annum of the average unused portion of the Credit Facility and a loan service fee, both paid quarterly. The Credit Facility is secured by all of the Company's assets in accordance with the terms of the Credit Facility.

The Credit Facility requires the Company to maintain (i) a liquidity threshold of at least $20 million of unrestricted cash; (ii) a tangible net worth, plus unrestricted cash of at least 1.75x the amount then outstanding under the Credit Facility; (iii) a minimum aggregate appraised value of the Company’s ownership interests in its partner companies, plus unrestricted cash in excess of the liquidity threshold of at least $350 million; and (iv) certain diversification requirements and concentration limits with respect to the Company’s capital deployments to its partner companies. Subject to customary exclusions, the Lender has the right to have one observer representative attend meetings of the Company's Board of Directors.

The Credit Facility provides for customary events of default which include (subject in certain cases to customary grace and cure periods), among others, nonpayment of principal or interest; non-compliance with debt covenants; defaults in, or failure to pay, certain other indebtedness; the rendering of judgments to pay certain amounts of money; and certain events of bankruptcy or insolvency. Generally, if an event of default occurs and is not cured within the time periods specified (if any), the Lender may declare the outstanding amount under the Credit Facility to be immediately due and payable.

At March 31, 2018, the principal amount outstanding under the Credit Facility was $50.0 million, the unamortized discount and debt issuance costs were $4.3 million and the net carrying value of the credit facility was $45.7 million. The Company is amortizing the excess of the principal amount of the Credit Facility over its carrying value over the three-year term as additional interest expense using the effective interest method. For the three months ended March 31, 2018, the Company recorded $1.8 million of interest expense and made cash interest payments of $1.3 million under the Credit Facility. The effective interest rate on the Credit Facility is 15.0%.

Convertible Debentures

In November 2012, the Company issued $55.0 million principal amount of its 5.25% convertible senior debentures due on May 15, 2018 (the “2018 Debentures”). Interest on the 2018 Debentures is payable semi-annually. In July and June 2017, the Company repurchased on the open market, and retired, an aggregate of $14.0 million face value of the 2018 Debentures at a cost of $14.5 million, including transaction fees. At March 31, 2018, the Company had $41.0 million of outstanding 2018 Debentures.

The 2018 Debentures may be settled in cash or partially in cash upon conversion. Accordingly, the Company separately accounts for the liability and equity components of the 2018 Debentures. The carrying amount of the liability component was determined at the transaction date by measuring the fair value of a similar liability that does not have an associated equity component. The carrying amount of the equity component represented by the embedded conversion option was determined by deducting the fair value of the liability component from the initial proceeds of the 2018 Debentures as a whole.

At March 31, 2018, the carrying amount of the equity component was $5.6 million, the principal amount of the liability component was $41.0 million, the unamortized discount and debt issuance costs were $0.2 million and the net carrying value of the liability component was $40.8 million. The Company is amortizing the excess of the face value of the 2018 Debentures over their carrying value over their term as additional interest expense using the effective interest method. The Company recorded interest expense of $0.9 million and $1.1 million for the three months ended March 31, 2018 and 2017, respectively. The cash interest paid was zero for the three months ended March 31, 2018 and 2017. The effective interest rate on the 2018 Debentures is 8.7%. At March 31, 2018, the fair value of the $41.0 million outstanding 2018 Debentures was approximately $41.3 million, based on the midpoint of the bid and ask prices as of such date. The Company anticipates refinancing the outstanding 2018 Debentures by the maturity date of May 15, 2018.