XML 29 R21.htm IDEA: XBRL DOCUMENT v3.20.1
Research and Development
12 Months Ended
Dec. 31, 2019
Research And Development [Abstract]  
Research and Development

(11) Research and Development

Research and development expenses which are included in operating expenses were $8,906, $9,164 and $8,455 for the years ended December 31, 2019, 2018 and 2017, respectively.