General General (Policies)	3 Months Ended
Mar. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Recent Accounting Pronouncements	Recently Adopted Accounting Pronouncements In May 2014, the Financial Accounting Standards Board ("FASB") issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) ("ASU 2014-09"). ASU 2014-09 and related subsequent amendments outline a single comprehensive model to use to account for revenue arising from contracts with customers and supersede most current revenue recognition guidance. For public companies, the guidance is effective for annual periods beginning after December 15, 2017 and any interim periods that fall within that reporting period. For nonpublic companies, the guidance was effective for annual periods beginning after December 15, 2018 and interim periods within annual periods beginning after December 15, 2019 with early adoption permitted. As the new standard superseded most existing revenue guidance, it could impact revenue and cost recognition for partner companies. Any change in revenue or cost recognition for partner companies could affect the Company's recognition of its share of the results of its equity method partner companies. On July 20, 2017, the SEC staff observer at the FASB’s Emerging Issues Task Force ("EITF") meeting announced that the SEC staff will not object if a private company equity method investee meeting the definition of a public business entity that otherwise would not meet the definition of a public business entity except for the inclusion of its financial statements or financial information in another entity’s filings with the SEC, uses private company adoption dates for the new revenue standard. As a result, the Company's private, calendar year partner companies will adopt the new revenue standard for the year ending December 31, 2019. The impact of adoption of the new revenue standard will be reflected in the Company’s financial results for the interim and annual reporting periods beginning in 2020 on a one quarter-lag basis. In February 2016, the FASB issued ASU 2016-02, Leases. The guidance in ASU 2016-02 requires that a lessee recognize in the statement of financial position a liability to make lease payments (the lease liability) and a right-of-use asset representing its right to use the underlying asset for the lease term. For leases with a term of 12 months or less, a lessee is permitted to make an accounting policy election by class of underlying asset not to recognize lease assets and lease liabilities. As with previous guidance, there continues to be a differentiation between finance leases and operating leases, however this distinction now primarily relates to differences in the manner of expense recognition over time and in the classification of lease payments in the statement of cash flows. Lease assets and liabilities arising from both finance and operating leases will be recognized in the statement of financial position. The transitional guidance for adopting the requirements of ASU 2016-02 calls for a modified retrospective approach that includes a number of optional practical expedients that entities may elect to apply. The guidance in ASU 2016-02 became effective for the Company on January 1, 2019. The Company elected the package of practical expedients permitted under the transition guidance within the new standard, which, among other things, allowed the Company to carry forward its historical lease classification. In addition, the Company has elected to exempt short term leases that qualify from recognizing right of use assets or lease liabilities, and has elected to not separate lease and non-lease components for all leases of which it is the lessee. The Company’s non-lease components are primarily related to utility and maintenance costs, which are typically variable in nature and are expensed in the period incurred. As of January 1, 2019, the Company's only material long-term lease was for its corporate headquarters in Radnor, PA under a lease expiring in 2026. The Company also has immaterial office equipment leases expiring at various dates through 2020. The Company recorded an initial lease liability of $2.9 million, a right-of-use asset of $2.2 million included in property and equipment and eliminated the deferred rent liability of $0.7 million that was previously included in other long-term liabilities.

Recently Adopted Accounting Pronouncements

In May 2014, the Financial Accounting Standards Board ("FASB") issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606) ("ASU 2014-09"). ASU 2014-09 and related subsequent amendments outline a single comprehensive model to use to account for revenue arising from contracts with customers and supersede most current revenue recognition guidance. For public companies, the guidance is effective for annual periods beginning after December 15, 2017 and any interim periods that fall within that reporting period. For nonpublic companies, the guidance was effective for annual periods beginning after December 15, 2018 and interim periods within annual periods beginning after December 15, 2019 with early adoption permitted. As the new standard superseded most existing revenue guidance, it could impact revenue and cost recognition for partner companies. Any change in revenue or cost recognition for partner companies could affect the Company's recognition of its share of the results of its equity method partner companies. On July 20, 2017, the SEC staff observer at the FASB’s Emerging Issues Task Force ("EITF") meeting announced that the SEC staff will not object if a private company equity method investee meeting the definition of a public business entity that otherwise would not meet the definition of a public business entity except for the inclusion of its financial statements or financial information in another entity’s filings with the SEC, uses private company adoption dates for the new revenue standard. As a result, the Company's private, calendar year partner companies will adopt the new revenue standard for the year ending December 31, 2019. The impact of adoption of the new revenue standard will be reflected in the Company’s financial results for the interim and annual reporting periods beginning in 2020 on a one quarter-lag basis.

In February 2016, the FASB issued ASU 2016-02, Leases. The guidance in ASU 2016-02 requires that a lessee recognize in the statement of financial position a liability to make lease payments (the lease liability) and a right-of-use asset representing its right to use the underlying asset for the lease term. For leases with a term of 12 months or less, a lessee is permitted to make an accounting policy election by class of underlying asset not to recognize lease assets and lease liabilities. As with previous guidance, there continues to be a differentiation between finance leases and operating leases, however this distinction now primarily relates to differences in the manner of expense recognition over time and in the classification of lease payments in the statement of cash flows. Lease assets and liabilities arising from both finance and operating leases will be recognized in the statement of financial position. The transitional guidance for adopting the requirements of ASU 2016-02 calls for a modified retrospective approach that includes a number of optional practical expedients that entities may elect to apply. The guidance in ASU 2016-02 became effective for the Company on January 1, 2019. The Company elected the package of practical expedients permitted under the transition guidance within the new standard, which, among other things, allowed the Company to carry forward its historical lease classification. In addition, the Company has elected to exempt short term leases that qualify from recognizing right of use assets or lease liabilities, and has elected to not separate lease and non-lease components for all leases of which it is the lessee. The Company’s non-lease components are primarily related to utility and maintenance costs, which are typically variable in nature and are expensed in the period incurred. As of January 1, 2019, the Company's only material long-term lease was for its corporate headquarters in Radnor, PA under a lease expiring in 2026. The Company also has immaterial office equipment leases expiring at various dates through 2020. The Company recorded an initial lease liability of $2.9 million, a right-of-use asset of $2.2 million included in property and equipment and eliminated the deferred rent liability of $0.7 million that was previously included in other long-term liabilities.