Subsequent Events	12 Months Ended
Dec. 31, 2019
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events Public Offering of Common Stock Pursuant to the Shelf Registration Statement on Form S-3 which was declared effective by the SEC on January 2, 2020 and the Final Prospectus Supplement dated January 22, 2020, on January 27, 2020, the Company sold 2,490,053 shares at a follow-on public offering price of $21.50 per share for a net proceeds of $50.3 million to the Company, after deducting the underwriting discounts and commissions but before offering expenses. Upon completion of the offering and issuance of common stock, the Company had 27,708,111 shares of common stock outstanding. The Company also granted the underwriters an option for a period of 30 days from the date of filing the prospectus supplement to purchase up to 645,000 additional shares of the Company's common stock at a public offering price of $21.50 per share. On February 24, 2020, the underwriters fully exercised its option to purchase additional shares of the Company's common stock for an additional net proceeds of $13.0 million to the Company, after deducting the underwriting discounts and commissions. The Company intends to use the net proceeds from this offering to support the continued commercial expansion of its iFuse system, sales and marketing, surgeon training and clinical studies, as well as working capital and general corporate purposes. The Company may also use a portion of the net proceeds to acquire or invest in complementary products, technologies, or businesses; however, the Company currently has no agreements or commitments to complete any such transactions. In addition to the shares sold by the Company in the public offering, on January 27, 2020, the selling stockholders sold 1,809,947 shares of the Company’s common stock previously held by the selling shareholders at a price to the public of $21.50 per share. The Company did not receive any proceeds from the sales by the selling shareholders. In conjunction with the sales by the selling shareholders, the Company incurred offering costs associated with the selling of shares by the selling shareholders, which will be recognized as transaction costs within general and administrative expenses on consolidated statement of operations in the first quarter of 2020. Settlement Agreement On January 14, 2020, the Company entered into a definitive settlement agreement related to an outstanding legal proceeding. For information regarding this legal proceeding, refer to Legal Proceedings in “Note 6 - Commitments and Contingencies” in the accompanying Notes to Consolidated Financial Statements. Joint Development Agreement with a Related Party On February 24, 2020, the Company entered into a joint development agreement (the "Development Agreement") with SeaSpine Orthopedics Corporation ("SeaSpine") to develop a next generation device for sacropelvic fixation. Mr. Keith Valentine, who serves as the President, Chief Executive Officer and a member of the board of directors of SeaSpine, also serves as a member of the Company's Board of Directors since August 2015. Pursuant to the development Plan, SeaSpine shall use reasonable efforts to assist in the develop of the potential product offering, including licensing certain existing intellectual property to be incorporated into such product. Under the terms of the Development Agreement, the Company agreed to make monthly payments of approximately $10,000 to SeaSpine to reimburse for full time resources employed by SeaSpine responsible to conduct the development activities. Certain intellectual property developed pursuant to the project plan will be owned by the Company, certain intellectual property developed pursuant to the project plan will be owned by SeaSpine, and other intellectual property developed pursuant to the project plan will be jointly owned by SeaSpine and the Company. The Company also agreed to provide SeaSpine a royalty-free, worldwide, perpetual, non-exclusive license of certain of the Company's intellectual property incorporated into the product to be developed. The Company also agreed to pay SeaSpine a product royalty, in an amount specified in the Development Agreement, for each resulting product sold for a period of 10 years beginning on the initial market launch. The term of the Development Agreement shall continue until the expiration of all royalty terms, unless earlier terminated by either parties, in situations defined in the Development Agreement.

Subsequent Events

Public Offering of Common Stock

Pursuant to the Shelf Registration Statement on Form S-3 which was declared effective by the SEC on January 2, 2020 and the Final Prospectus Supplement dated January 22, 2020, on January 27, 2020, the Company sold 2,490,053 shares at a follow-on public offering price of $21.50 per share for a net proceeds of $50.3 million to the Company, after deducting the underwriting discounts and commissions but before offering expenses. Upon completion of the offering and issuance of common stock, the Company had 27,708,111 shares of common stock outstanding. The Company also granted the underwriters an option for a period of 30 days from the date of filing the prospectus supplement to purchase up to 645,000 additional shares of the Company's common stock at a public offering price of $21.50 per share. On February 24, 2020, the underwriters fully exercised its option to purchase additional shares of the Company's common stock for an additional net proceeds of $13.0 million to the Company, after deducting the underwriting discounts and commissions. The Company intends to use the net proceeds from this offering to support the continued commercial expansion of its iFuse system, sales and marketing, surgeon training and clinical studies, as well as working capital and general corporate purposes. The Company may also use a portion of the net proceeds to acquire or invest in complementary products, technologies, or businesses; however, the Company currently has no agreements or commitments to complete any such transactions.

In addition to the shares sold by the Company in the public offering, on January 27, 2020, the selling stockholders sold 1,809,947 shares of the Company’s common stock previously held by the selling shareholders at a price to the public of $21.50 per share. The Company did not receive any proceeds from the sales by the selling shareholders. In conjunction with the sales by the selling shareholders, the Company incurred offering costs associated with the selling of shares by the selling shareholders, which will be recognized as transaction costs within general and administrative expenses on consolidated statement of operations in the first quarter of 2020.

Settlement Agreement

On January 14, 2020, the Company entered into a definitive settlement agreement related to an outstanding legal proceeding. For information regarding this legal proceeding, refer to Legal Proceedings in “Note 6 - Commitments and Contingencies” in the accompanying Notes to Consolidated Financial Statements.

Joint Development Agreement with a Related Party

On February 24, 2020, the Company entered into a joint development agreement (the "Development Agreement") with SeaSpine Orthopedics Corporation ("SeaSpine") to develop a next generation device for sacropelvic fixation. Mr. Keith Valentine, who serves as the President, Chief Executive Officer and a member of the board of directors of SeaSpine, also serves as a member of the Company's Board of Directors since August 2015.

Pursuant to the development Plan, SeaSpine shall use reasonable efforts to assist in the develop of the potential product offering, including licensing certain existing intellectual property to be incorporated into such product. Under the terms of the Development Agreement, the Company agreed to make monthly payments of approximately $10,000 to SeaSpine to reimburse for full time resources employed by SeaSpine responsible to conduct the development activities. Certain intellectual property developed pursuant to the project plan will be owned by the Company, certain intellectual property developed pursuant to the project plan will be owned by SeaSpine, and other intellectual property developed pursuant to the project plan will be jointly owned by SeaSpine and the Company. The Company also agreed to provide SeaSpine a royalty-free, worldwide, perpetual, non-exclusive license of certain of the Company's intellectual property incorporated into the product to be developed. The Company also agreed to pay SeaSpine a product royalty, in an amount specified in the Development Agreement, for each resulting product sold for a period of 10 years beginning on the initial market launch. The term of the Development Agreement shall continue until the expiration of all royalty terms, unless earlier terminated by either parties, in situations defined in the Development Agreement.