Acquisitions and Divestitures - Restore Flow Allografts - Additional Information (Detail) - USD ($)		3 Months Ended								12 Months Ended
	Nov. 10, 2016	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Fair value adjustments to contingent consideration obligations										$ 106,000
Net revenue		$ 26,153,000	$ 24,822,000	$ 25,753,000	$ 24,139,000	$ 23,288,000	$ 23,216,000	$ 22,389,000	$ 20,258,000	$ 100,867,000	$ 89,151,000	$ 78,352,000
Weighted average useful life										8 years
Restore Flow Allografts [Member]
Business Acquisition [Line Items]
Initial purchase price	$ 12,000,000
Acquisition-related contingent consideration	$ 900,000
Additional payment description										The first payment of $2 million is due not later than 15 days following the expiration of the 18 month period following the closing date, subject to reductions as specified in the agreement for each calendar month that certain retained employees are not employed by us due to resignation without good reason, or termination for cause, both as defined in the agreement. The portion of this payment that will be paid to retained employees and that is contingent on their continued employment, estimated at $0.9 million, will be accounted for as post-combination compensation expense rather than purchase consideration. The remaining $1.1 million that is payable to non-employee investors but that is also contingent on the continued employment of certain retained employees has been accounted for as contingent consideration, at an acquisition-date fair value of $0.9 million. This valuation reflects management’s assessment of the likelihood that the retained employees will remain employed by us, discounted at a rate of 6.1% to account for risk inherent in the probability estimate as well as for the time value of money between acquisition date and the payment date. There are also two potential earn-out payments under the agreement. The first earn-out is calculated at 50% of the amount by which net revenue in the first 12 months following the closing exceeds $6 million, with such payout not to exceed $2 million. The second earn-out is calculated at 50% of the amount by which net revenue in the second 12 months following the closing exceeds $9 million, with such payout not to exceed $2 million.
Fair value inputs, discount rate	6.10%
Fair value adjustments to contingent consideration obligations										$ 100,000
Estimated weighted average cost of capital	14.10%
Maximum goodwill deductible for tax purposes										15 years
Weighted average useful life										10 years 3 months 18 days
Restore Flow Allografts [Member] | Non-employee Investors [Member]
Business Acquisition [Line Items]
Acquisition-related contingent consideration	$ 1,100,000
Acquisition-date fair value	900,000
Restore Flow Allografts [Member] | Maximum [Member]
Business Acquisition [Line Items]
Acquisition-related contingent consideration	6,000,000
Contingency One [Member] | Restore Flow Allografts [Member]
Business Acquisition [Line Items]
Acquisition-related contingent consideration	2,000,000
Earn - Outs Payment One [Member] | Restore Flow Allografts [Member] | Maximum [Member]
Business Acquisition [Line Items]
Acquisition-related contingent consideration	2,000,000
Earn - Outs Payment One [Member] | Restore Flow Allografts [Member] | Minimum [Member]
Business Acquisition [Line Items]
Net revenue	6,000,000
Earn - Outs Payment Two [Member] | Restore Flow Allografts [Member] | Maximum [Member]
Business Acquisition [Line Items]
Acquisition-related contingent consideration	2,000,000
Earn - Outs Payment Two [Member] | Restore Flow Allografts [Member] | Minimum [Member]
Business Acquisition [Line Items]
Net revenue	9,000,000
Combined Earn-out Payment [Member] | Restore Flow Allografts [Member]
Business Acquisition [Line Items]
Acquisition-date fair value	$ 100,000