Summary of Significant Accounting Policies (Policies)	6 Months Ended
Jun. 30, 2021
Accounting Policies [Abstract]
Cash and Cash Equivalents and Concentration	Cash and Cash Equivalents and Concentration The Company considers highly liquid investments with maturities of three months or less at the date of acquisition as cash equivalents in the accompanying condensed consolidated financial statements. The Company has not experienced any losses related to these balances; however, as of June 30, 2021, $52,578 of the cash and cash equivalents balance was in excess of Federal Deposit Insurance Corporation limits. As of June 30, 2021 and December 31, 2020, the Company had restricted cash balances of $6,333 and $6,842, respectively. The June 30, 2021 and December 31, 2020 balances both include $6,000, which represents collateral for an irrevocable standby letter of credit. The June 30, 2021 and December 31, 2020 balances include $83 and $842, respectively, which is the balance of the Heights Union Escrow Account (see Note 13 - Commitments and Contingencies). Additionally, the June 30, 2021 balance includes an additional irrevocable standby letter of credit in the amount of $250 (See Note 10 - Long Term Debt).
Revenue Recognition	Revenue Recognition The Company enters into contracts to sell and distribute products and services to hospitals and surgical facilities for use in caring for patients with peripheral nerve damage or transection. Revenue is recognized when the Company has met its performance obligations pursuant to its contracts with its customers in an amount that the Company expects to be entitled to in exchange for the transfer of control of the products and services to the Company’s customers. In the case of products or services sold to a customer under a distribution or purchase agreement, the customers are granted exclusive distribution rights to sell the implants internationally in a territory defined by the contract. These international distributor agreements contain provisions that allow the Company to terminate the distribution agreement with the distributor, and upon termination, the right to repurchase inventory from the distributor at the distributor’s cost. The Company has determined that its contractual rights to repurchase distributor inventory upon termination of the distributor agreement are not substantive and do not impact the timing of when control transfers; and, therefore, the Company has determined it is appropriate to recognize revenue when: i) the product is shipped via common carrier; or ii) the product is delivered to the customer or distributor, depending on the terms of the agreement. Determining the timing of revenue recognition for such contracts is subject to judgment, because an evaluation must be made regarding the distributor’s ability to direct the use of, and obtain substantially all of the remaining benefits from, the implants received from the Company. Changes in these assessments could have an impact on the timing of revenue recognition from sales to distributors. A portion of the Company’s product revenue is generated from consigned inventory maintained at hospitals and independent sales agencies, and also from inventory physically held by field sales representatives. For these types of products sales, the Company retains control until the product has been used or implanted, at which time revenue is recognized. The Company accounts for shipping and handling activities as a fulfillment cost rather than a separate performance obligation. Amounts billed to customers for shipping and handling are included as part of the transaction price and recognized as revenue when control of the underlying products is transferred to the customer. The related shipping and freight charges incurred by the Company are included in cost of sales. The Company operates in a single reportable segment of peripheral nerve repair, offers similar products to its customers, and enters into consistently structured arrangements with similar types of customers. As such, the Company does not disaggregate revenue from contracts with customers as the nature, amount, timing and uncertainty of revenue and cash flows does not materially differ within and among the contracts with customers. The contract with the customer states the final terms of the sale, including the description, quantity, and price of each implant distributed. The payment terms and conditions in the Company’s contracts vary; however, as a common business practice, payment terms are typically due in full within thirty to sixty days of delivery. Since the customer agrees to a stated price in the contract that does not vary over the contract term, the contracts do not contain any material types of variable consideration, and contractual rights of return are not material. The Company has several contracts with distributors in international markets which include consideration paid to the customer in exchange for distinct marketing and other services. The Company records such consideration paid to the customer as a reduction to revenue from the contracts with those distributor customers. In connection with the Acroval Neurosensory and Motor Testing System, the Company sold extended warranty and service packages to some of its customers who purchased this evaluation and measurement tool, and the prepayment of these extended warranties represent contract liabilities until the performance obligations are satisfied ratably over the term of the contract. The sale of the aforementioned extended warranty represents the only performance obligation the Company satisfies over time and creates the contract liability disclosed below.
Allowance for Doubtful Accounts Receivable and Concentration of Credit Risk	Allowance for Doubtful Accounts Receivable and Concentration of Credit Risk The Company evaluates the collectability of accounts receivable to determine the appropriate allowance for doubtful accounts. In determining the amount of the allowance, the Company considers aging of account balances, historical credit losses, customer-specific information, the current economic environment, supportable forecasts and other relevant factors. An increase to the allowance for doubtful accounts results in a corresponding increase in general and administrative expense. The Company reviews accounts receivable and adjusts the allowance based on current circumstances and charges off uncollectible receivables against the allowance when all attempts to collect the receivable have failed. The Company’s history of write-offs has not been significant. The allowance for doubtful accounts balance was approximately $258 and $416 at June 30, 2021 and December 31, 2020, respectively. Concentrations of credit risk with respect to accounts receivable are limited because a large number of geographically diverse customers make up the Company’s customer base, thus spreading the credit risk. The Company also controls credit risk through credit approvals and monitoring procedures.
Derivative Instruments	Derivative Instruments The Company analyzes all financial instruments with features under Accounting Standards Codification ("ASC") 480, “Distinguishing Liabilities from Equity” and ASC 815, “Derivatives and Hedging”. The Company also reviews debt agreements for embedded features. If these features are not clearly and closely related to the debt host, they meet the definition of a derivative and require bifurcation from the host. All derivative instruments are recorded on the balance sheet at their respective fair values. The Company will adjust the carrying value of the derivative liability to fair value at each subsequent reporting date. The changes in the value of the derivatives are recorded in the consolidated statement of operations in the period in which they occur.
Net Loss Per Share	Net Loss Per Share Basic net loss per share is computed by dividing reported net loss by the weighted average number of common shares outstanding for the reported period. Diluted net loss per share reflects the potential dilution that could occur if securities or other contracts to issue common stock were exercised or converted into common stock of the Company during the reporting period. Diluted net loss per share is computed by dividing net loss by the sum of the weighted average number of common shares and the number of potential dilutive common share equivalents outstanding during the period. Potential dilutive common share equivalents consist of the incremental common shares issuable upon the exercise of vested share options and the incremental shares issuable upon conversion of the convertible notes. Potential dilutive common share equivalents consist of stock options, restricted stock units (“RSUs”), and performance stock units (“PSUs”).

Summary of Significant Accounting Policies (Policies)

6 Months Ended

Jun. 30, 2021

Cash and Cash Equivalents and Concentration

The Company considers highly liquid investments with maturities of three months or less at the date of acquisition as cash equivalents in the accompanying condensed consolidated financial statements. The Company has not experienced any losses related to these balances; however, as of June 30, 2021, $52,578 of the cash and cash equivalents balance was in excess of Federal Deposit Insurance Corporation limits. As of June 30, 2021 and December 31, 2020, the Company had restricted cash balances of $6,333 and $6,842, respectively. The June 30, 2021 and December 31, 2020 balances both include $6,000, which represents collateral for an irrevocable standby letter of credit. The June 30, 2021 and December 31, 2020 balances include $83 and $842, respectively, which is the balance of the Heights Union Escrow Account (see Note 13 - Commitments and Contingencies). Additionally, the June 30, 2021 balance includes an additional irrevocable standby letter of credit in the amount of $250 (See Note 10 - Long Term Debt).

Revenue Recognition

The Company enters into contracts to sell and distribute products and services to hospitals and surgical facilities for use in caring for patients with peripheral nerve damage or transection. Revenue is recognized when the Company has met its performance obligations pursuant to its contracts with its customers in an amount that the Company expects to be entitled to in exchange for the transfer of control of the products and services to the Company’s customers.

In the case of products or services sold to a customer under a distribution or purchase agreement, the customers are granted exclusive distribution rights to sell the implants internationally in a territory defined by the contract. These international distributor agreements contain provisions that allow the Company to terminate the distribution agreement with the distributor, and upon termination, the right to repurchase inventory from the distributor at the distributor’s cost. The Company has determined that its contractual rights to repurchase distributor inventory upon termination of the distributor agreement are not substantive and do not impact the timing of when control transfers; and, therefore, the Company has determined it is appropriate to recognize revenue when: i) the product is shipped via common carrier; or ii) the product is delivered to the customer or distributor, depending on the terms of the agreement. Determining the timing of revenue recognition for such contracts is subject to judgment, because an evaluation must be made regarding the distributor’s ability to direct the use of, and obtain substantially all of the remaining benefits from, the implants received from the Company. Changes in these assessments could have an impact on the timing of revenue recognition from sales to distributors.

A portion of the Company’s product revenue is generated from consigned inventory maintained at hospitals and independent sales agencies, and also from inventory physically held by field sales representatives. For these types of products sales, the Company retains control until the product has been used or implanted, at which time revenue is recognized.

The Company accounts for shipping and handling activities as a fulfillment cost rather than a separate performance obligation. Amounts billed to customers for shipping and handling are included as part of the transaction price and recognized as revenue when control of the underlying products is transferred to the customer. The related shipping and freight charges incurred by the Company are included in cost of sales.

The Company operates in a single reportable segment of peripheral nerve repair, offers similar products to its customers, and enters into consistently structured arrangements with similar types of customers. As such, the Company does not disaggregate revenue from contracts with customers as the nature, amount, timing and uncertainty of revenue and cash flows does not materially differ within and among the contracts with customers.

The contract with the customer states the final terms of the sale, including the description, quantity, and price of each implant distributed. The payment terms and conditions in the Company’s contracts vary; however, as a common business practice, payment terms are typically due in full within thirty to sixty days of delivery. Since the customer agrees to a stated price in the contract that does not vary over the contract term, the contracts do not contain any material types of variable consideration, and contractual rights of return are not material. The Company has several contracts with distributors in international markets which include consideration paid to the customer in exchange for distinct marketing and other services. The Company records such consideration paid to the customer as a reduction to revenue from the contracts with those distributor customers.

In connection with the Acroval Neurosensory and Motor Testing System, the Company sold extended warranty and service packages to some of its customers who purchased this evaluation and measurement tool, and the prepayment of these extended warranties represent contract liabilities until the performance obligations are satisfied ratably over the term of the contract. The sale of the aforementioned extended warranty represents the only performance obligation the Company satisfies over time and creates the contract liability disclosed below.

Allowance for Doubtful Accounts Receivable and Concentration of Credit Risk

The Company evaluates the collectability of accounts receivable to determine the appropriate allowance for doubtful accounts. In determining the amount of the allowance, the Company considers aging of account balances, historical credit losses, customer-specific information, the current economic environment, supportable forecasts and other relevant factors. An increase to the allowance for doubtful accounts results in a corresponding increase in general and administrative expense. The Company reviews accounts receivable and adjusts the allowance based on current circumstances and charges off uncollectible receivables against the allowance when all attempts to collect the receivable have failed. The Company’s history of write-offs has not been significant. The allowance for doubtful accounts balance was approximately $258 and $416 at June 30, 2021 and December 31, 2020, respectively.

Concentrations of credit risk with respect to accounts receivable are limited because a large number of geographically diverse customers make up the Company’s customer base, thus spreading the credit risk. The Company also controls credit risk through credit approvals and monitoring procedures.

Derivative Instruments

The Company analyzes all financial instruments with features under Accounting Standards Codification ("ASC") 480, “Distinguishing Liabilities from Equity” and ASC 815, “Derivatives and Hedging”. The Company also reviews debt agreements for embedded features. If these features are not clearly and closely related to the debt host, they meet the definition of a derivative and require bifurcation from the host. All derivative instruments are recorded on the balance sheet at their respective fair values. The Company will adjust the carrying value of the derivative liability to fair value at each subsequent reporting date. The changes in the value of the derivatives are recorded in the consolidated statement of operations in the period in which they occur.

Net Loss Per Share

Basic net loss per share is computed by dividing reported net loss by the weighted average number of common shares outstanding for the reported period. Diluted net loss per share reflects the potential dilution that could occur if securities or other contracts to issue common stock were exercised or converted into common stock of the Company during the reporting period. Diluted net loss per share is computed by dividing net loss by the sum of the weighted average number of common shares and the number of potential dilutive common share equivalents outstanding during the period. Potential dilutive common share equivalents consist of the incremental common shares issuable upon the exercise of vested share options and the incremental shares issuable upon conversion of the convertible notes. Potential dilutive common share equivalents consist of stock options, restricted stock units (“RSUs”), and performance stock units (“PSUs”).