QUARTERLY FINANCIAL INFORMATION (UNAUDITED) (Details) - USD ($) $ / shares in Units, $ in Thousands |
3 Months Ended | 12 Months Ended | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2017 |
Sep. 30, 2017 |
Jun. 30, 2017 |
Mar. 31, 2017 |
Dec. 31, 2016 |
Sep. 30, 2016 |
Jun. 30, 2016 |
Mar. 31, 2016 |
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| Organization, Consolidation and Presentation of Financial Statements [Abstract] | |||||||||||
| Net revenue | $ 11,681 | $ 12,375 | $ 11,802 | $ 9,762 | $ 9,418 | $ 10,135 | $ 9,674 | $ 8,071 | $ 45,620 | $ 37,298 | $ 31,004 |
| Cost of revenue | 8,832 | 9,491 | 8,712 | 7,415 | 6,400 | 7,157 | 6,826 | 5,984 | 11,170 | 10,931 | 9,367 |
| Operating loss | (4,204) | (754) | (677) | (837) | (3,252) | (524) | (865) | (1,486) | (6,472) | (6,127) | (6,592) |
| Net loss | (4,845) | (1,536) | (1,266) | (1,285) | (3,633) | (846) | (288) | (1,805) | (8,932) | (6,572) | (7,891) |
| Net loss attributable to common stockholders | $ (15,078) | $ (3,021) | $ (2,720) | $ (2,711) | $ (5,289) | $ (2,405) | $ (1,688) | $ (3,066) | $ (23,530) | $ (12,448) | $ (12,688) |
| Net loss per share attributable to common stockholders - basic and diluted (in dollars per share) | $ (1.41) | $ (1.70) | $ (1.56) | $ (1.55) | $ (3.03) | $ (1.38) | $ (0.97) | $ (1.76) | $ (5.86) | $ (7.14) | $ (7.27) |