| Guarantor and Non-Guarantor Financial Statements - Condensed Statement of Operations and Comprehensive Loss (Details) - USD ($)$ in Thousands
 | 3 Months Ended | 9 Months Ended | 
| Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2018 | Dec. 31, 2017 | 
| Condensed Income Statements, Captions [Line Items] |  |  |  |  | 
| Net revenues | $ 30,411 | $ 22,732 | $ 76,377 | $ 53,790 | 
| Cost of revenues |  |  |  |  | 
| License fees and revenue share | 19,195 | 14,887 | 50,213 | 34,344 | 
| Other direct cost of revenues | 538 | 437 | 1,553 | 1,276 | 
| Total cost of revenues | 19,733 | 15,324 | 51,766 | 35,620 | 
| Gross profit | 10,678 | 7,408 | 24,611 | 18,170 | 
| Operating expenses |  |  |  |  | 
| Product development | 2,428 | 3,120 | 8,174 | 7,535 | 
| Sales and marketing | 1,962 | 1,623 | 5,711 | 4,044 | 
| General and administrative | 3,832 | 4,152 | 9,215 | 11,061 | 
| Total operating expenses | 8,222 | 8,895 | 23,100 | 22,640 | 
| Income / (loss) from operations | 2,456 | (1,487) | 1,511 | (4,470) | 
| Interest and other income / (expense), net |  |  |  |  | 
| Interest expense | (194) | (446) | (648) | (1,815) | 
| Foreign exchange transaction gain / (loss) | (2) | 49 | 7 | (61) | 
| Change in fair value of convertible note embedded derivative liability | (1,476) | (1,658) | 1,096 | (6,310) | 
| Change in fair value of warrant liability | (1,651) | (898) | 845 | (2,526) | 
| Loss on extinguishment of debt | (10) | (285) | (25) | (1,167) | 
| Other expense | (43) | (154) | (169) | (73) | 
| Total interest and other income / (expense), net | (3,376) | (3,392) | 1,106 | (11,952) | 
| Income / (loss) from continuing operations before income taxes | (920) | (4,879) | 2,617 | (16,422) | 
| Income tax provision | 216 | (84) | 157 | (937) | 
| Net income / (loss) from continuing operations, net of taxes | (1,136) | (4,795) | 2,460 | (15,485) | 
| Loss from discontinued operations | (212) | 996 | (1,612) | 1,053 | 
| Net income / (loss) | (1,348) | (3,799) | 848 | (14,432) | 
| Foreign currency translation adjustment | (5) | 0 | (5) | (5) | 
| Comprehensive income / (loss) | (1,353) | (3,799) | 843 | (14,437) | 
| Elimination |  |  |  |  | 
| Condensed Income Statements, Captions [Line Items] |  |  |  |  | 
| Net revenues | (24,680) | (19,169) | (63,791) | (44,721) | 
| Cost of revenues |  |  |  |  | 
| License fees and revenue share | (24,680) | (19,169) | (63,791) | (44,721) | 
| Other direct cost of revenues | 0 | 0 | 0 |  | 
| Total cost of revenues | (24,680) | (19,169) | (63,791) | (44,721) | 
| Gross profit | 0 | 0 | 0 | 0 | 
| Operating expenses |  |  |  |  | 
| Product development | 0 | 0 | 0 | 0 | 
| Sales and marketing | 0 | 0 | 0 | 0 | 
| General and administrative | 0 | 0 | 0 | 0 | 
| Total operating expenses | 0 | 0 | 0 | 0 | 
| Income / (loss) from operations | 0 | 0 | 0 | 0 | 
| Interest and other income / (expense), net |  |  |  |  | 
| Interest expense | 0 | 0 | 0 | 0 | 
| Foreign exchange transaction gain / (loss) | 0 | 0 | 0 | 0 | 
| Change in fair value of convertible note embedded derivative liability | 0 | 0 | 0 | 0 | 
| Change in fair value of warrant liability | 0 | 0 | 0 | 0 | 
| Loss on extinguishment of debt | 0 | 0 | 0 | 0 | 
| Other expense | 0 | 0 | 0 | 0 | 
| Total interest and other income / (expense), net | 0 | 0 | 0 | 0 | 
| Income / (loss) from continuing operations before income taxes | 0 | 0 | 0 | 0 | 
| Income tax provision | 0 | 0 | 0 | 0 | 
| Net income / (loss) from continuing operations, net of taxes | 0 | 0 | 0 | 0 | 
| Loss from discontinued operations | 0 | 0 | 0 | 0 | 
| Net income / (loss) | 0 | 0 | 0 | 0 | 
| Foreign currency translation adjustment | 0 |  | 0 | 0 | 
| Comprehensive income / (loss) | 0 | 0 | 0 | 0 | 
| Parent | Reportable Legal Entities |  |  |  |  | 
| Condensed Income Statements, Captions [Line Items] |  |  |  |  | 
| Net revenues | 0 | 0 | 0 | 0 | 
| Cost of revenues |  |  |  |  | 
| License fees and revenue share | 0 | 0 | 0 | 0 | 
| Other direct cost of revenues | 0 | 0 | 0 | 0 | 
| Total cost of revenues | 0 | 0 | 0 | 0 | 
| Gross profit | 0 | 0 | 0 | 0 | 
| Operating expenses |  |  |  |  | 
| Product development | 84 | 2 | 256 | 14 | 
| Sales and marketing | 121 | 75 | 479 | 249 | 
| General and administrative | 3,126 | 3,682 | 5,540 | 8,327 | 
| Total operating expenses | 3,331 | 3,759 | 6,275 | 8,590 | 
| Income / (loss) from operations | (3,331) | (3,759) | (6,275) | (8,590) | 
| Interest and other income / (expense), net |  |  |  |  | 
| Interest expense | (118) | (446) | (572) | (1,815) | 
| Foreign exchange transaction gain / (loss) | 1 | 0 | 1 | 0 | 
| Change in fair value of convertible note embedded derivative liability | (1,476) | (1,658) | 1,096 | (6,310) | 
| Change in fair value of warrant liability | (1,651) | (898) | 845 | (2,526) | 
| Loss on extinguishment of debt | (10) | (285) | (25) | (1,167) | 
| Other expense | (76) | 28 | 842 | 7 | 
| Total interest and other income / (expense), net | (3,330) | (3,259) | 2,187 | (11,811) | 
| Income / (loss) from continuing operations before income taxes | (6,661) | (7,018) | (4,088) | (20,401) | 
| Income tax provision | 216 | (88) | 157 | (941) | 
| Net income / (loss) from continuing operations, net of taxes | (6,877) | (6,930) | (4,245) | (19,460) | 
| Loss from discontinued operations | 0 | (87) | (37) | (160) | 
| Net income / (loss) | (6,877) | (7,017) | (4,282) | (19,620) | 
| Foreign currency translation adjustment | 0 |  | 0 | 0 | 
| Comprehensive income / (loss) | (6,877) | (7,017) | (4,282) | (19,620) | 
| Guarantor Subsidiaries | Reportable Legal Entities |  |  |  |  | 
| Condensed Income Statements, Captions [Line Items] |  |  |  |  | 
| Net revenues | 54,843 | 41,679 | 139,536 | 97,772 | 
| Cost of revenues |  |  |  |  | 
| License fees and revenue share | 44,050 | 33,995 | 113,999 | 78,899 | 
| Other direct cost of revenues | 538 | 437 | 1,553 | 1,276 | 
| Total cost of revenues | 44,588 | 34,432 | 115,552 | 80,175 | 
| Gross profit | 10,255 | 7,247 | 23,984 | 17,597 | 
| Operating expenses |  |  |  |  | 
| Product development | 2,233 | 3,057 | 7,572 | 7,430 | 
| Sales and marketing | 1,635 | 1,441 | 4,626 | 3,566 | 
| General and administrative | 706 | 347 | 3,541 | 2,417 | 
| Total operating expenses | 4,574 | 4,845 | 15,739 | 13,413 | 
| Income / (loss) from operations | 5,681 | 2,402 | 8,245 | 4,184 | 
| Interest and other income / (expense), net |  |  |  |  | 
| Interest expense | (76) | 0 | (76) | 0 | 
| Foreign exchange transaction gain / (loss) | 2 | 48 | 27 | (62) | 
| Change in fair value of convertible note embedded derivative liability | 0 | 0 | 0 | 0 | 
| Change in fair value of warrant liability | 0 | 0 | 0 | 0 | 
| Loss on extinguishment of debt | 0 | 0 | 0 | 0 | 
| Other expense | 34 | (182) | (1,006) | (80) | 
| Total interest and other income / (expense), net | (40) | (134) | (1,055) | (142) | 
| Income / (loss) from continuing operations before income taxes | 5,641 | 2,268 | 7,190 | 4,042 | 
| Income tax provision | 0 | 6 | 0 | 6 | 
| Net income / (loss) from continuing operations, net of taxes | 5,641 | 2,262 | 7,190 | 4,036 | 
| Loss from discontinued operations | (212) | 1,278 | (1,584) | 1,854 | 
| Net income / (loss) | 5,429 | 3,540 | 5,606 | 5,890 | 
| Foreign currency translation adjustment | (5) |  | (5) | (5) | 
| Comprehensive income / (loss) | 5,424 | 3,540 | 5,601 | 5,885 | 
| Non-Guarantor Subsidiaries | Reportable Legal Entities |  |  |  |  | 
| Condensed Income Statements, Captions [Line Items] |  |  |  |  | 
| Net revenues | 248 | 222 | 632 | 739 | 
| Cost of revenues |  |  |  |  | 
| License fees and revenue share | (175) | 61 | 5 | 166 | 
| Other direct cost of revenues | 0 | 0 | 0 | 0 | 
| Total cost of revenues | (175) | 61 | 5 | 166 | 
| Gross profit | 423 | 161 | 627 | 573 | 
| Operating expenses |  |  |  |  | 
| Product development | 111 | 61 | 346 | 91 | 
| Sales and marketing | 206 | 107 | 606 | 229 | 
| General and administrative | 0 | 123 | 134 | 317 | 
| Total operating expenses | 317 | 291 | 1,086 | 637 | 
| Income / (loss) from operations | 106 | (130) | (459) | (64) | 
| Interest and other income / (expense), net |  |  |  |  | 
| Interest expense | 0 | 0 | 0 | 0 | 
| Foreign exchange transaction gain / (loss) | (5) | 1 | (21) | 1 | 
| Change in fair value of convertible note embedded derivative liability | 0 | 0 | 0 | 0 | 
| Change in fair value of warrant liability | 0 | 0 | 0 | 0 | 
| Loss on extinguishment of debt | 0 | 0 | 0 | 0 | 
| Other expense | (1) | 0 | (5) | 0 | 
| Total interest and other income / (expense), net | (6) | 1 | (26) | 1 | 
| Income / (loss) from continuing operations before income taxes | 100 | (129) | (485) | (63) | 
| Income tax provision | 0 | (2) | 0 | (2) | 
| Net income / (loss) from continuing operations, net of taxes | 100 | (127) | (485) | (61) | 
| Loss from discontinued operations | 0 | (195) | 9 | (641) | 
| Net income / (loss) | 100 | (322) | (476) | (702) | 
| Foreign currency translation adjustment | 0 |  | 0 | 0 | 
| Comprehensive income / (loss) | $ 100 | $ (322) | $ (476) | $ (702) |