| Contracts with Customer, Assets and Liabilities | 
Deferred revenue consisted of the following: 
 |  
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 
   | 
September 30,  2019  | 
   | 
December 31,  2018  | 
 
Deferred extended maintenance and support  | 
$  | 
2,826  | 
 
  | 
   | 
$  | 
2,114  | 
 
  | 
 
Deferred royalties  | 
290  | 
 
  | 
   | 
300  | 
 
  | 
 
Deferred rental income  | 
8  | 
 
  | 
   | 
51  | 
 
  | 
 
Customer deposits and advances  | 
73  | 
 
  | 
   | 
62  | 
 
  | 
 
Deferred device revenues  | 
47  | 
 
  | 
   | 
70  | 
 
  | 
 
Total deferred revenues  | 
3,244  | 
 
  | 
   | 
2,597  | 
 
  | 
 
Less current portion  | 
(1,398  | 
)  | 
   | 
(1,102  | 
)  | 
 
Deferred revenues, non-current  | 
$  | 
1,846  | 
 
  | 
   | 
$  | 
1,495  | 
 
  | 
 
  
 
Deferred revenue activity consisted of the following for the nine months ended September 30, 2019: 
 |  
 | 
 | 
 | 
 | 
 
Beginning balance  | 
$  | 
2,597  | 
 
  | 
 
Deferral of revenue  | 
2,013  | 
 
  | 
 
Recognition of deferred revenue  | 
(1,366  | 
)  | 
 
Ending balance  | 
$  | 
3,244  | 
 
  | 
 
  
 
 | 
| Disaggregation of Revenue | 
The following table disaggregates the Company’s revenue by major source for the three months ended September 30, 2019:
 
 |  
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 
   | 
EksoHealth  | 
   | 
EksoWorks  | 
   | 
Other  | 
   | 
Total  | 
 
Device revenue  | 
$  | 
2,373  | 
 
  | 
   | 
$  | 
289  | 
 
  | 
   | 
$  | 
—  | 
 
  | 
   | 
$  | 
2,662  | 
 
  | 
 
Service, support and rentals  | 
567  | 
 
  | 
   | 
—  | 
 
  | 
   | 
—  | 
 
  | 
   | 
567  | 
 
  | 
 
Parts and other  | 
41  | 
 
  | 
   | 
31  | 
 
  | 
   | 
—  | 
 
  | 
   | 
72  | 
 
  | 
 
Collaborative arrangements  | 
—  | 
 
  | 
   | 
—  | 
 
  | 
   | 
18  | 
 
  | 
   | 
18  | 
 
  | 
 
   | 
$  | 
2,981  | 
 
  | 
   | 
$  | 
320  | 
 
  | 
   | 
$  | 
18  | 
 
  | 
   | 
$  | 
3,319  | 
 
  | 
 
  
  
The following table disaggregates the Company’s revenue by major source for the nine months ended September 30, 2019:
 
 |  
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 
   | 
EksoHealth  | 
   | 
EksoWorks  | 
   | 
Other  | 
   | 
Total  | 
 
Device revenue  | 
$  | 
6,613  | 
 
  | 
   | 
$  | 
1,365  | 
 
  | 
   | 
$  | 
—  | 
 
  | 
   | 
$  | 
7,978  | 
 
  | 
 
Service, support and rentals  | 
1,941  | 
 
  | 
   | 
—  | 
 
  | 
   | 
—  | 
 
  | 
   | 
1,941  | 
 
  | 
 
Parts and other  | 
81  | 
 
  | 
   | 
171  | 
 
  | 
   | 
—  | 
 
  | 
   | 
252  | 
 
  | 
 
Collaborative arrangements  | 
—  | 
 
  | 
   | 
—  | 
 
  | 
   | 
26  | 
 
  | 
   | 
26  | 
 
  | 
 
   | 
$  | 
8,635  | 
 
  | 
   | 
$  | 
1,536  | 
 
  | 
   | 
$  | 
26  | 
 
  | 
   | 
$  | 
10,197  | 
 
  | 
 
  
  
The following table disaggregates the Company’s revenue by major source for the three months ended September 30, 2018:
 
 |  
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 
   | 
EksoHealth  | 
   | 
EksoWorks  | 
   | 
Other  | 
   | 
Total  | 
 
Device revenue  | 
$  | 
1,084  | 
 
  | 
   | 
$  | 
736  | 
 
  | 
   | 
$  | 
—  | 
 
  | 
   | 
$  | 
1,820  | 
 
  | 
 
Service, support and rentals  | 
644  | 
 
  | 
   | 
9  | 
 
  | 
   | 
—  | 
 
  | 
   | 
653  | 
 
  | 
 
Parts and other  | 
16  | 
 
  | 
   | 
44  | 
 
  | 
   | 
—  | 
 
  | 
   | 
60  | 
 
  | 
 
Collaborative arrangements  | 
—  | 
 
  | 
   | 
—  | 
 
  | 
   | 
17  | 
 
  | 
   | 
17  | 
 
  | 
 
   | 
$  | 
1,744  | 
 
  | 
   | 
$  | 
789  | 
 
  | 
   | 
$  | 
17  | 
 
  | 
   | 
$  | 
2,550  | 
 
  | 
 
  
  
The following table disaggregates the Company’s revenue by major source for the nine months ended September 30, 2018:
 
 |  
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 | 
 
   | 
EksoHealth  | 
   | 
EksoWorks  | 
   | 
Other  | 
   | 
Total  | 
 
Device revenue  | 
$  | 
4,691  | 
 
  | 
   | 
$  | 
1,669  | 
 
  | 
   | 
$  | 
—  | 
 
  | 
   | 
$  | 
6,360  | 
 
  | 
 
Service, support and rentals  | 
1,425  | 
 
  | 
   | 
9  | 
 
  | 
   | 
—  | 
 
  | 
   | 
1,434  | 
 
  | 
 
Parts and other  | 
150  | 
 
  | 
   | 
64  | 
 
  | 
   | 
—  | 
 
  | 
   | 
214  | 
 
  | 
 
Collaborative arrangements  | 
—  | 
 
  | 
   | 
—  | 
 
  | 
   | 
28  | 
 
  | 
   | 
28  | 
 
  | 
 
   | 
$  | 
6,266  | 
 
  | 
   | 
$  | 
1,742  | 
 
  | 
   | 
$  | 
28  | 
 
  | 
   | 
$  | 
8,036  | 
 
  | 
 
  
 
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