Fair Value Measurements - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended
	Jan. 01, 2018	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amortized cost basis in debt security		$ 9,000
Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of debt securities		16,050	$ 16,050	$ 9,000	$ 12,220
Bone Biologics Inc [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Purchase of common stock, value		$ 500
Bone Biologics Inc [Member] | Common Stock [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Purchase of stock, shares		250,000
ASU 2016-01 [Member] | Bone Biologics Inc [Member] | Equity Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Increase in previously recorded value of equity investments resulted from new measurement	$ 1,600
Impact on remeasurement of equity investments per share before taxes included within other income	$ 0.09