Notes Receivable and Other Long-term Receivables (Narrative) (Detail)																1 Months Ended					12 Months Ended			58 Months Ended
	Dec. 15, 2015 USD ($) shares	Nov. 12, 2015 USD ($)	Oct. 27, 2015 USD ($)	Oct. 07, 2015 $ / shares	Oct. 06, 2015 $ / shares	Sep. 22, 2015 USD ($)	Jun. 26, 2015 USD ($) $ / shares shares	Feb. 23, 2015 USD ($)	Nov. 14, 2014 USD ($)	Nov. 10, 2014 USD ($)	Feb. 14, 2014 USD ($)	Nov. 05, 2013 USD ($)	Nov. 02, 2013 USD ($)	Oct. 03, 2013 USD ($)	Aug. 15, 2013 USD ($)	Apr. 30, 2013 USD ($)	Feb. 28, 2013 USD ($)	Jan. 31, 2013 USD ($)	Oct. 31, 2012 USD ($)	Mar. 31, 2012 USD ($)	Dec. 31, 2015 USD ($) $ / shares shares	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Apr. 30, 2018	Dec. 01, 2015 USD ($)	Nov. 11, 2015 $ / shares shares	Oct. 28, 2015 USD ($)	Sep. 29, 2015 USD ($)	Sep. 15, 2015 shares	May. 12, 2015 USD ($)	Dec. 12, 2014 USD ($) $ / shares shares	Nov. 09, 2014	May. 27, 2014 USD ($)	Apr. 01, 2014 USD ($)	Feb. 06, 2014 $ / shares	Nov. 06, 2013 USD ($)	Oct. 31, 2013 USD ($)	Aug. 14, 2013 USD ($) $ / shares shares	Jun. 28, 2013 USD ($)	Apr. 18, 2013 USD ($)	Mar. 05, 2013 USD ($)	Nov. 02, 2012 USD ($)	Aug. 31, 2012 USD ($)	Jan. 27, 2012 USD ($)
Accounts Notes And Loans Receivable [Line Items]
Financing receivable, gross																																								$ 20,000,000
Repayment of notes receivable						$ 21,400,000															$ 25,242,000	$ 68,800,000	$ 59,279,000
Investment Owned, Balance, Shares | shares	1,700,000
Share Price | $ / shares																																			$ 7.97
Investment Owned, at Fair Value																					1,500,000
Equity investment, shares sold (shares) | shares																										149,650			200,000
Proceeds from Sale of Available-for-sale Securities		$ 1,900,000
Investment Owned, Unrecognized Unrealized Appreciation																					$ 700,000
Commitments and Contingencies
Gain (Loss) on Sale of Notes Receivable																					$ (3,979,000)	$ 0	$ 0
Warrants and Rights Outstanding																					1,000,000
Wellstat Diagnostics [Member]
Accounts Notes And Loans Receivable [Line Items]
Financing receivable, gross																					53,900,000
Financing receivable, modification, cost as a component of interest and other income, net															$ 2,500,000
Interest rate of note receivable (in Percent)															5.00%
Financing Receivable, Net																					50,200,000
Asset Management Costs																					$ 12,900,000
AxoGen [Member]
Accounts Notes And Loans Receivable [Line Items]
Repayment of notes receivable									$ 30,300,000
Investment Owned, Balance, Shares | shares																					293,732										643,382							1,166,666
Share Price | $ / shares																										$ 5.46					$ 2.72							$ 3.00
Investment Owned, at Cost																															$ 1,700,000							$ 3,500,000
Price per share of investment sold | $ / shares																															$ 3.03
Proceeds from Sale of Available-for-sale Securities, Equity								$ 3,500,000
Avinger [Member]
Accounts Notes And Loans Receivable [Line Items]
Repayment of notes receivable						$ 21,400,000
LENSAR [Member]
Accounts Notes And Loans Receivable [Line Items]
Financing receivable, gross	$ 42,000,000													$ 40,000,000
Interest rate of note receivable (in Percent)														15.50%																18.50%
Amount company has agreed to advance under agreement														$ 60,000,000
Commitments and Contingencies																														$ 8,500,000
Gain (Loss) on Sale of Notes Receivable	4,000,000
Other General and Administrative Expense	3,000,000
Durata [Member]
Accounts Notes And Loans Receivable [Line Items]
Financing receivable, gross																																	$ 15,000,000				$ 25,000,000
Interest rate of note receivable (in Percent)																																					14.00%
Repayment of notes receivable									$ 42,700,000
Amount company has agreed to advance under agreement													$ 70,000,000
DirectFlow [Member]
Accounts Notes And Loans Receivable [Line Items]
Financing receivable, gross																																				$ 35,000,000
Interest rate of note receivable (in Percent)																																13.50%				15.50%
Amount company has agreed to advance under agreement										$ 15,000,000		$ 50,000,000
Hyperion [Member]
Accounts Notes And Loans Receivable [Line Items]
Financing receivable, gross																																												$ 2,300,000
Periodic contractual payments																																									$ 1,200,000
First minimum payment																																									$ 1,200,000
Number of payments to be received																																												2
Paradigm Spine [Member]
Accounts Notes And Loans Receivable [Line Items]
Financing receivable, gross											$ 50,000,000
Interest rate of note receivable (in Percent)											13.00%
Amount company has agreed to advance under agreement			$ 7,000,000								$ 75,000,000
Maximum amount of additional funds, upon attainment of milestones											$ 25,000,000
Tranche 1 of note receivable																											$ 4,000,000
Tranche 2 of note receivable																											$ 3,000,000
kaleo Note Receivable [Member]
Accounts Notes And Loans Receivable [Line Items]
Financing receivable, gross																																		$ 150,000,000
Interest rate of note receivable (in Percent)																																		13.00%
Note receivable payment received																									$ 9,500,000
Interest reserve balance																																		$ 20,000,000
Alphaeon [Member]
Accounts Notes And Loans Receivable [Line Items]
Investment estimated fair value, per share | $ / shares																					$ 3.84
Cost Method Investments, Original Cost	6,600,000
CareView [Member]
Accounts Notes And Loans Receivable [Line Items]
Interest rate of note receivable (in Percent)							13.50%
Amount company has agreed to advance under agreement							$ 40,000,000
Tranche 1 of note receivable							20,000,000
Tranche 2 of note receivable							$ 20,000,000
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | shares							4,400,000
Class of Warrant or Right, Exercise Price of Warrants or Rights | $ / shares							$ 0.45
Investment Warrants, Exercise Price | $ / shares				$ 0.40	$ 0.45
Notes Receivable [Member] | Wellstat Diagnostics [Member]
Accounts Notes And Loans Receivable [Line Items]
Financing receivable, gross																				$ 7,500,000																							$ 10,000,000
Term of receivable (in Duration)																				2 years
Interest rate of note receivable (in Percent)																				10.00%																							12.00%
Notes Receivable [Member] | Avinger [Member]
Accounts Notes And Loans Receivable [Line Items]
Financing receivable, gross																																								$ 20,000,000
Interest rate of note receivable (in Percent)																																								12.00%
Amount company has agreed to advance under agreement																$ 40,000,000
Credit Agreement [Member] | Wellstat Diagnostics [Member]
Accounts Notes And Loans Receivable [Line Items]
Financing receivable, gross																																										$ 40,000,000
Credit agreement, stated interest rate (in Percent)																																										5.00%
Proceeds received under remedies available for borrower's breach of terms credit agreement																		$ 8,100,000
Amount company has agreed to advance under agreement																	$ 7,900,000				$ 8,700,000
Financing Receivable, Modifications, Post-Modification Recorded Investment															$ 44,100,000
Forbearance period under terms of credit agreement (in Duration)																	120 days
Initial Loan [Member] | Wellstat Diagnostics [Member]
Accounts Notes And Loans Receivable [Line Items]
Financing Receivable, Modifications, Pre-Modification Recorded Investment															33,700,000
Additional Loan [Member]
Accounts Notes And Loans Receivable [Line Items]
Commitments and Contingencies																												$ 800,000		$ 500,000
Additional Loan [Member] | Wellstat Diagnostics [Member]
Accounts Notes And Loans Receivable [Line Items]
Financing receivable, gross																																							$ 1,300,000
Additional Loan [Member] | LENSAR [Member]
Accounts Notes And Loans Receivable [Line Items]
Amount company has agreed to advance under agreement														$ 20,000,000
Royalty Agreement [Member] | AxoGen [Member]
Accounts Notes And Loans Receivable [Line Items]
Term of receivable (in Duration)																			8 years
Royalty rate on AxoGen net revenues (in percent)																			9.95%
Guaranteed quarterly minimum payment-low																			$ 1,300,000
Guaranteed quarterly minimum payment-high																			$ 2,500,000
Term of royalty agreement (in Duration)																			8 years
Total consideration paid to AxoGen for the royalty rights																			$ 20,800,000
Initial interim funding for royalty rights																			$ 1,800,000
Royalty Agreement [Member] | Avinger [Member]
Accounts Notes And Loans Receivable [Line Items]
Reduction in royalty rate (in percent)																								50.00%
Term loan and interest [Member] | Wellstat Diagnostics [Member]
Accounts Notes And Loans Receivable [Line Items]
Financing Receivable, Modifications, Pre-Modification Recorded Investment															1,300,000
Forbearance principal and interest [Member] | Wellstat Diagnostics [Member]
Accounts Notes And Loans Receivable [Line Items]
Financing Receivable, Modifications, Pre-Modification Recorded Investment															$ 9,100,000
Tranche two [Member] | Durata [Member]
Accounts Notes And Loans Receivable [Line Items]
Interest rate of note receivable (in Percent)																																					12.75%
Tranche two [Member] | DirectFlow [Member]
Accounts Notes And Loans Receivable [Line Items]
Financing receivable, gross																																				$ 15,000,000
Tranche three [Member] | DirectFlow [Member]
Accounts Notes And Loans Receivable [Line Items]
Financing receivable, gross	$ 5,000,000