Note 15 - Intellectual Property - License Agreements	12 Months Ended
Dec. 31, 2019
Notes to Financial Statements
License Agreements [Text Block]	15. Intellectual property—license agreements The Company entered into three license agreements by which it has secured certain patent rights that are necessary to make, use and sell the T-SPOT. TB test. In November 2013, one of these license agreements, with Oxford Innovation, was terminated in connection with the assignment by Oxford Innovation to the Company of certain intellectual property rights. The Company has ongoing obligations to make certain payments to Oxford Innovation while the assigned patents remain in force in certain countries. On June 30, 2017, we entered into a Release and Settlement Agreement, or the Settlement Agreement, with Statens Serum Institut, or SSI, to resolve outstanding disputes arising from the license agreement with SSI. The terms of the Settlement Agreement are confidential. Based on the Settlement Agreement, we no longer expect to pay royalties to SSI. The Company’s existing license agreements related to its T-SPOT. TB test, as well as its previous license from Oxford Innovation, are generally exclusive in the stated field, cover a worldwide territory, are royalty-bearing and give the Company the right to grant sublicenses. The Company has minimum royalty obligations under each existing license agreement, which continue so long as patents licensed under the agreements remain unexpired. The Company incurs royalties under each existing license agreement and has incurred royalties under the Oxford Innovation license agreement based on its product and service revenue. Effective January 2020, the Company’s payment obligations to Oxford Innovation in respect of amounts treated as royalties will cease. The aggregate royalty expense relating to these license agreements amounted to $1.4 million and $1.1 million for the years ended December 31, 2019 and 2018 , respectively. The Company paid other license-related expenses, including patent prosecution expenses, milestone payments and assignment fees due to these licensors, amounting to $44,000 and $83,000 for the years ended December 31, 2019 and 2018 , respectively. The aggregate royalty rate paid by the Company in each of the years ended December 31, 2019 and 2018 , as a percentage of the gross product and service revenue of the Company, was 2% .

15.

Intellectual property—license agreements

The Company entered into

three

license agreements by which it has secured certain patent rights that are necessary to make, use and sell the T-SPOT.

test. In

November 2013,

one

of these license agreements, with Oxford Innovation, was terminated in connection with the assignment by Oxford Innovation to the Company of certain intellectual property rights. The Company has ongoing obligations to make certain payments to Oxford Innovation while the assigned patents remain in force in certain countries.

June 30, 2017,

we entered into a Release and Settlement Agreement, or the Settlement Agreement, with Statens Serum Institut, or SSI, to resolve outstanding disputes arising from the license agreement with SSI. The terms of the Settlement Agreement are confidential. Based on the Settlement Agreement, we

longer expect to pay royalties to SSI.

The Company’s existing license agreements related to its T-SPOT.

test, as well as its previous license from Oxford Innovation, are generally exclusive in the stated field, cover a worldwide territory, are royalty-bearing and give the Company the right to grant sublicenses. The Company has minimum royalty obligations under each existing license agreement, which continue so long as patents licensed under the agreements remain unexpired.

The Company incurs royalties under each existing license agreement and has incurred royalties under the Oxford Innovation license agreement based on its product and service revenue. Effective

January 2020,

the Company’s payment obligations to Oxford Innovation in respect of amounts treated as royalties will cease. The aggregate royalty expense relating to these license agreements amounted to

$1.4

million and

$1.1

million for the years ended

December 31, 2019

and

2018

, respectively. The Company paid other license-related expenses, including patent prosecution expenses, milestone payments and assignment fees due to these licensors, amounting to

$44,000

and

$83,000

for the years ended

December 31, 2019

and

2018

, respectively. The aggregate royalty rate paid by the Company in each of the years ended

December 31, 2019

and

2018

, as a percentage of the gross product and service revenue of the Company, was