Guarantor and Non-Guarantor Financial Statements - Income Statement (Details) - USD ($)  $ in Thousands  | 
3 Months Ended | 
6 Months Ended | 
Sep. 30, 2018  | 
Sep. 30, 2017  | 
Sep. 30, 2018  | 
Sep. 30, 2017  | 
| Condensed Income Statements, Captions [Line Items] | 
 
 | 
 
 | 
 
 | 
 
 | 
| Net revenues | 
$ 23,854
 | 
$ 15,905
 | 
$ 45,966
 | 
$ 31,058
 | 
| Cost of revenues | 
 
 | 
 
 | 
 
 | 
 
 | 
| License fees and revenue share | 
15,802
 | 
9,865
 | 
31,018
 | 
19,457
 | 
| Other direct cost of revenues | 
508
 | 
430
 | 
1,015
 | 
839
 | 
| Total cost of revenues | 
16,310
 | 
10,295
 | 
32,033
 | 
20,296
 | 
| Gross profit | 
7,544
 | 
5,610
 | 
13,933
 | 
10,762
 | 
| Operating expenses | 
 
 | 
 
 | 
 
 | 
 
 | 
| Product development | 
2,637
 | 
2,241
 | 
5,746
 | 
4,415
 | 
| Sales and marketing | 
1,913
 | 
1,284
 | 
3,749
 | 
2,421
 | 
| General and administrative | 
2,679
 | 
3,551
 | 
5,383
 | 
6,909
 | 
| Total operating expenses | 
7,229
 | 
7,076
 | 
14,878
 | 
13,745
 | 
| Income / (loss) from operations | 
315
 | 
(1,466)
 | 
(945)
 | 
(2,983)
 | 
| Interest and other income / (expense), net | 
 
 | 
 
 | 
 
 | 
 
 | 
| Interest expense | 
(135)
 | 
(662)
 | 
(454)
 | 
(1,369)
 | 
| Foreign exchange transaction gain / (loss) | 
1
 | 
(47)
 | 
9
 | 
(110)
 | 
| Change in fair value of convertible note embedded derivative liability | 
952
 | 
(3,344)
 | 
2,572
 | 
(4,652)
 | 
| Change in fair value of warrant liability | 
926
 | 
(1,164)
 | 
2,496
 | 
(1,628)
 | 
| Loss on extinguishment of debt | 
(15)
 | 
(882)
 | 
(15)
 | 
(882)
 | 
| Other income / (expense) | 
1
 | 
78
 | 
(126)
 | 
81
 | 
| Total interest and other income / (expense), net | 
1,730
 | 
(6,021)
 | 
4,482
 | 
(8,560)
 | 
| Income / (loss) from continuing operations before income taxes | 
2,045
 | 
(7,487)
 | 
3,537
 | 
(11,543)
 | 
| Income tax benefit | 
(23)
 | 
(884)
 | 
(59)
 | 
(853)
 | 
| Net income / (loss) from continuing operations, net of taxes | 
2,068
 | 
(6,603)
 | 
3,596
 | 
(10,690)
 | 
| Loss from discontinued operations | 
(356)
 | 
145
 | 
(1,400)
 | 
57
 | 
| Net income / (loss) | 
1,712
 | 
(6,458)
 | 
2,196
 | 
(10,633)
 | 
| Foreign currency translation adjustment | 
0
 | 
(5)
 | 
0
 | 
(5)
 | 
| Comprehensive income / (loss) | 
1,712
 | 
(6,463)
 | 
2,196
 | 
(10,638)
 | 
| Elimination | 
 
 | 
 
 | 
 
 | 
 
 | 
| Condensed Income Statements, Captions [Line Items] | 
 
 | 
 
 | 
 
 | 
 
 | 
| Net revenues | 
(20,092)
 | 
(13,388)
 | 
(39,111)
 | 
(25,552)
 | 
| Cost of revenues | 
 
 | 
 
 | 
 
 | 
 
 | 
| License fees and revenue share | 
(20,092)
 | 
(13,388)
 | 
(39,111)
 | 
(25,552)
 | 
| Other direct cost of revenues | 
0
 | 
0
 | 
0
 | 
 
 | 
| Total cost of revenues | 
(20,092)
 | 
(13,388)
 | 
(39,111)
 | 
(25,552)
 | 
| 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 income / (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 benefit | 
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
 | 
| Comprehensive income / (loss) | 
0
 | 
0
 | 
0
 | 
0
 | 
| Parent | 
 
 | 
 
 | 
 
 | 
 
 | 
| Interest and other income / (expense), net | 
 
 | 
 
 | 
 
 | 
 
 | 
| Change in fair value of warrant liability | 
 
 | 
 
 | 
 
 | 
(1,628)
 | 
| Net income / (loss) from continuing operations, net of taxes | 
208
 | 
(7,661)
 | 
2,632
 | 
(12,530)
 | 
| Loss from discontinued operations | 
0
 | 
(73)
 | 
(37)
 | 
(73)
 | 
| 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 | 
82
 | 
7
 | 
172
 | 
12
 | 
| Sales and marketing | 
234
 | 
72
 | 
358
 | 
174
 | 
| General and administrative | 
1,252
 | 
2,393
 | 
2,414
 | 
4,645
 | 
| Total operating expenses | 
1,568
 | 
2,472
 | 
2,944
 | 
4,831
 | 
| Income / (loss) from operations | 
(1,568)
 | 
(2,472)
 | 
(2,944)
 | 
(4,831)
 | 
| Interest and other income / (expense), net | 
 
 | 
 
 | 
 
 | 
 
 | 
| Interest expense | 
(134)
 | 
(659)
 | 
(454)
 | 
(1,369)
 | 
| Foreign exchange transaction gain / (loss) | 
0
 | 
0
 | 
0
 | 
0
 | 
| Change in fair value of convertible note embedded derivative liability | 
952
 | 
(3,344)
 | 
2,572
 | 
(4,652)
 | 
| Change in fair value of warrant liability | 
926
 | 
(1,164)
 | 
2,496
 | 
(1,628)
 | 
| Loss on extinguishment of debt | 
(15)
 | 
(882)
 | 
(15)
 | 
(882)
 | 
| Other income / (expense) | 
24
 | 
(24)
 | 
918
 | 
(21)
 | 
| Total interest and other income / (expense), net | 
1,753
 | 
(6,073)
 | 
5,517
 | 
(8,552)
 | 
| Income / (loss) from continuing operations before income taxes | 
185
 | 
(8,545)
 | 
2,573
 | 
(13,383)
 | 
| Income tax benefit | 
(23)
 | 
(884)
 | 
(59)
 | 
(853)
 | 
| Net income / (loss) from continuing operations, net of taxes | 
 
 | 
 
 | 
2,632
 | 
(12,530)
 | 
| Net income / (loss) | 
208
 | 
(7,734)
 | 
2,595
 | 
(12,603)
 | 
| Foreign currency translation adjustment | 
 
 | 
0
 | 
 
 | 
0
 | 
| Comprehensive income / (loss) | 
208
 | 
(7,734)
 | 
2,595
 | 
(12,603)
 | 
| Guarantor Subsidiaries | Reportable Legal Entities | 
 
 | 
 
 | 
 
 | 
 
 | 
| Condensed Income Statements, Captions [Line Items] | 
 
 | 
 
 | 
 
 | 
 
 | 
| Net revenues | 
43,766
 | 
29,026
 | 
84,693
 | 
56,093
 | 
| Cost of revenues | 
 
 | 
 
 | 
 
 | 
 
 | 
| License fees and revenue share | 
35,804
 | 
23,183
 | 
69,949
 | 
44,904
 | 
| Other direct cost of revenues | 
508
 | 
430
 | 
1,015
 | 
839
 | 
| Total cost of revenues | 
36,312
 | 
23,613
 | 
70,964
 | 
45,743
 | 
| Gross profit | 
7,454
 | 
5,413
 | 
13,729
 | 
10,350
 | 
| Operating expenses | 
 
 | 
 
 | 
 
 | 
 
 | 
| Product development | 
2,435
 | 
2,216
 | 
5,339
 | 
4,373
 | 
| Sales and marketing | 
1,483
 | 
1,143
 | 
2,991
 | 
2,125
 | 
| General and administrative | 
1,345
 | 
1,038
 | 
2,835
 | 
2,070
 | 
| Total operating expenses | 
5,263
 | 
4,397
 | 
11,165
 | 
8,568
 | 
| Income / (loss) from operations | 
2,191
 | 
1,016
 | 
2,564
 | 
1,782
 | 
| Interest and other income / (expense), net | 
 
 | 
 
 | 
 
 | 
 
 | 
| Interest expense | 
(1)
 | 
(3)
 | 
0
 | 
0
 | 
| Foreign exchange transaction gain / (loss) | 
15
 | 
(47)
 | 
25
 | 
(110)
 | 
| 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 income / (expense) | 
(24)
 | 
102
 | 
(1,040)
 | 
102
 | 
| Total interest and other income / (expense), net | 
(10)
 | 
52
 | 
(1,015)
 | 
(8)
 | 
| Income / (loss) from continuing operations before income taxes | 
2,181
 | 
1,068
 | 
1,549
 | 
1,774
 | 
| Income tax benefit | 
0
 | 
0
 | 
0
 | 
0
 | 
| Net income / (loss) from continuing operations, net of taxes | 
2,181
 | 
1,068
 | 
1,549
 | 
1,774
 | 
| Loss from discontinued operations | 
(356)
 | 
620
 | 
(1,372)
 | 
576
 | 
| Net income / (loss) | 
1,825
 | 
1,688
 | 
177
 | 
2,350
 | 
| Foreign currency translation adjustment | 
 
 | 
211
 | 
 
 | 
(5)
 | 
| Comprehensive income / (loss) | 
1,825
 | 
1,899
 | 
177
 | 
2,345
 | 
| Non-Guarantor Subsidiaries | Reportable Legal Entities | 
 
 | 
 
 | 
 
 | 
 
 | 
| Condensed Income Statements, Captions [Line Items] | 
 
 | 
 
 | 
 
 | 
 
 | 
| Net revenues | 
180
 | 
267
 | 
384
 | 
517
 | 
| Cost of revenues | 
 
 | 
 
 | 
 
 | 
 
 | 
| License fees and revenue share | 
90
 | 
70
 | 
180
 | 
105
 | 
| Other direct cost of revenues | 
0
 | 
0
 | 
0
 | 
0
 | 
| Total cost of revenues | 
90
 | 
70
 | 
180
 | 
105
 | 
| Gross profit | 
90
 | 
197
 | 
204
 | 
412
 | 
| Operating expenses | 
 
 | 
 
 | 
 
 | 
 
 | 
| Product development | 
120
 | 
18
 | 
235
 | 
30
 | 
| Sales and marketing | 
196
 | 
69
 | 
400
 | 
122
 | 
| General and administrative | 
82
 | 
120
 | 
134
 | 
194
 | 
| Total operating expenses | 
398
 | 
207
 | 
769
 | 
346
 | 
| Income / (loss) from operations | 
(308)
 | 
(10)
 | 
(565)
 | 
66
 | 
| Interest and other income / (expense), net | 
 
 | 
 
 | 
 
 | 
 
 | 
| Interest expense | 
0
 | 
0
 | 
0
 | 
0
 | 
| Foreign exchange transaction gain / (loss) | 
(14)
 | 
0
 | 
(16)
 | 
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 income / (expense) | 
1
 | 
0
 | 
(4)
 | 
0
 | 
| Total interest and other income / (expense), net | 
(13)
 | 
0
 | 
(20)
 | 
0
 | 
| Income / (loss) from continuing operations before income taxes | 
(321)
 | 
(10)
 | 
(585)
 | 
66
 | 
| Income tax benefit | 
0
 | 
0
 | 
0
 | 
0
 | 
| Net income / (loss) from continuing operations, net of taxes | 
(321)
 | 
(10)
 | 
(585)
 | 
66
 | 
| Loss from discontinued operations | 
0
 | 
(402)
 | 
9
 | 
(446)
 | 
| Net income / (loss) | 
(321)
 | 
(412)
 | 
(576)
 | 
(380)
 | 
| Foreign currency translation adjustment | 
 
 | 
(216)
 | 
 
 | 
0
 | 
| Comprehensive income / (loss) | 
$ (321)
 | 
$ (628)
 | 
$ (576)
 | 
$ (380)
 |