BUSINESS DEVELOPMENT	3 Months Ended
Mar. 31, 2019
Asset Acquisition [Abstract]
BUSINESS DEVELOPMENT	BUSINESS DEVELOPMENT Integrated Shoulder Collaboration, Inc. On January 4, 2019, the Company entered into a licensing agreement with Integrated Shoulder Collaboration, Inc ("ISC"). Under the terms of the agreement, the Company paid ISC $1.7 million for the exclusive, worldwide license to commercialize its short stem and stemless shoulder system. A patent related to short stem and stemless shoulder systems was issued to ISC during the first quarter of 2019. ISC is eligible to receive royalties on sales of the short stem and stemless shoulder system. The Company has the option to acquire ISC at a date four years subsequent to the first commercial sale, which becomes mandatory upon the achievement of a certain sales threshold of the short stem and stemless shoulder system, for an amount not to exceed $80.0 million. The transaction was accounted for as an asset acquisition as the Company concluded that it acquired primarily one asset. The total upfront payment of $1.7 million was expensed as a component of research and development expense and the future milestone and option payments will be recorded if the corresponding events become probable.

BUSINESS DEVELOPMENT

Integrated Shoulder Collaboration, Inc.

On January 4, 2019, the Company entered into a licensing agreement with Integrated Shoulder Collaboration, Inc ("ISC"). Under the terms of the agreement, the Company paid ISC $1.7 million for the exclusive, worldwide license to commercialize its short stem and stemless shoulder system. A patent related to short stem and stemless shoulder systems was issued to ISC during the first quarter of 2019. ISC is eligible to receive royalties on sales of the short stem and stemless shoulder system. The Company has the option to acquire ISC at a date four years subsequent to the first commercial sale, which becomes mandatory upon the achievement of a certain sales threshold of the short stem and stemless shoulder system, for an amount not to exceed $80.0 million. The transaction was accounted for as an asset acquisition as the Company concluded that it acquired primarily one asset. The total upfront payment of $1.7 million was expensed as a component of research and development expense and the future milestone and option payments will be recorded if the corresponding events become probable.