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Goodwill and Intangible Assets - Additional Information (Detail) - USD ($) | 3 Months Ended |
--- | --- | ---
Mar. 31, 2018 | Mar. 31, 2017 | Dec. 31, 2017
Goodwill And Intangible Assets [Line Items] |  |  |
Goodwill | $ 12,005,000 |  | $ 12,005,000
Description of annual goodwill impairment test | On January 1, 2017, the Company adopted ASU 2017-04, which eliminated the Step 2 requirement of the goodwill impairment test. Instead, the goodwill impairment test is performed by comparing the fair value of a reporting unit with its carrying amount. The Company determined that the decrease in its market capitalization in the first quarter of 2017 constituted an indicator of impairment and therefore a goodwill impairment test was completed as of March 31, 2017. |  |
Goodwill impairment | $ 0 | $ 1,958,000 |
Amortization expense of intangible assets | 600,000 | 600,000 |
Cost of Product [Member] |  |  |
Goodwill And Intangible Assets [Line Items] |  |  |
Amortization expense of intangible assets | 400,000 | 400,000 |
Sales and marketing expense [Member] |  |  |
Goodwill And Intangible Assets [Line Items] |  |  |
Amortization expense of intangible assets | 200,000 | 200,000 |
Post-Transplant [Member] |  |  |
Goodwill And Intangible Assets [Line Items] |  |  |
Goodwill | $ 12,000,000 |  | $ 12,000,000
Pre-Transplant [Member] |  |  |
Goodwill And Intangible Assets [Line Items] |  |  |
Description of goodwill impairment method for fair value determination | determined that the fair value of the Pre-Transplant reporting unit was $3.5 million, which was lower than its carrying value. |  |
Fair value of reporting unit |  | $ 3,500,000 |
Reporting unit, discount rate |  | 16.60% |
Reporting unit, terminal growth rate |  | 3.20% |
Reporting unit, capitalization multiple |  | $ 7.48 |
Pre-Transplant [Member] | Maximum [Member] |  |  |
Goodwill And Intangible Assets [Line Items] |  |  |
Goodwill impairment |  | $ 2,000,000 |

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- Definition The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6388964&loc=d3e16225-109274 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275 + Details
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- Definition Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=77989000&loc=SL49117168-202975 + Details
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- Definition Description of how the fair value of the impaired goodwill of the reporting unit was determined for goodwill valuation purposes. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 35 -Paragraph 22 -URI http://asc.fasb.org/extlink&oid=77993916&loc=d3e12382-109265 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 35 -Paragraph 23 -URI http://asc.fasb.org/extlink&oid=77993916&loc=d3e12407-109265 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13854-109267 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 35 -Paragraph 24 -URI http://asc.fasb.org/extlink&oid=77993916&loc=d3e12414-109265 + Details
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