Condensed Consolidating Financial Information - Statement of Operations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Revenue:
Service revenues	$ 26,069	$ 21,952	$ 71,851	$ 61,671
Subscriber equipment sales	4,389	3,592	11,382	10,795
Total revenue	30,458	25,544	83,233	72,466
Operating expenses:
Cost of services (exclusive of depreciation, amortization, and accretion shown separately below)	9,315	8,373	27,325	23,901
Cost of subscriber equipment sales	2,905	2,411	7,779	7,475
Marketing, general and administrative	9,616	10,077	28,650	30,137
Depreciation, amortization and accretion	19,415	19,446	57,984	57,825
Total operating expenses	41,251	40,307	121,738	119,338
Income (loss) from operations	(10,793)	(14,763)	(38,505)	(46,872)
Other income (expense):
Loss on extinguishment of debt	(6,306)	0	(6,306)
Gain (loss) on equity issuance	0	4,272	2,670	2,349
Interest income and expense, net of amounts capitalized	(8,954)	(8,866)	(26,632)	(27,020)
Derivative gain	78,840	10,982	4,933	50,137
Equity in subsidiary earnings (loss)	0	0	0	0
Other	(314)	(505)	(2,440)	(581)
Total other income (expense)	63,266	5,883	(27,775)	24,885
Income (loss) before income taxes	52,473	(8,880)	(66,280)	(21,987)
Income tax expense (benefit)	67	(6,303)	209	(6,562)
Net income (loss)	52,406	(2,577)	(66,489)	(15,425)
Comprehensive income (loss)	51,504	(2,493)	(68,256)	(16,917)
Reportable Legal Entities | Parent Company
Revenue:
Service revenues	20,018	23,996	56,315	51,878
Subscriber equipment sales	55	84	182	508
Total revenue	20,073	24,080	56,497	52,386
Operating expenses:
Cost of services (exclusive of depreciation, amortization, and accretion shown separately below)	6,460	5,178	19,003	15,126
Cost of subscriber equipment sales	8	(18)	74	169
Marketing, general and administrative	5,756	5,229	16,727	15,833
Depreciation, amortization and accretion	19,250	19,083	57,302	56,706
Total operating expenses	31,474	29,472	93,106	87,834
Income (loss) from operations	(11,401)	(5,392)	(36,609)	(35,448)
Other income (expense):
Loss on extinguishment of debt	(6,306)		(6,306)
Gain (loss) on equity issuance		4,272	2,705	2,349
Interest income and expense, net of amounts capitalized	(8,895)	(8,894)	(26,479)	(26,875)
Derivative gain	78,840	10,982	4,933	50,137
Equity in subsidiary earnings (loss)	754	(2,743)	(2,461)	(4,170)
Other	(586)	(802)	(2,272)	(1,418)
Total other income (expense)	63,807	2,815	(29,880)	20,023
Income (loss) before income taxes	52,406	(2,577)	(66,489)	(15,425)
Income tax expense (benefit)	0	0	0	0
Net income (loss)	52,406	(2,577)	(66,489)	(15,425)
Comprehensive income (loss)	52,406	(2,577)	(66,489)	(15,425)
Reportable Legal Entities | Guarantor Subsidiaries
Revenue:
Service revenues	10,163	7,529	29,365	25,887
Subscriber equipment sales	3,524	2,833	9,517	7,299
Total revenue	13,687	10,362	38,882	33,186
Operating expenses:
Cost of services (exclusive of depreciation, amortization, and accretion shown separately below)	1,523	2,538	4,351	4,608
Cost of subscriber equipment sales	2,494	2,108	7,317	5,648
Marketing, general and administrative	1,268	1,504	3,384	3,358
Depreciation, amortization and accretion	116	194	518	620
Total operating expenses	5,401	6,344	15,570	14,234
Income (loss) from operations	8,286	4,018	23,312	18,952
Other income (expense):
Loss on extinguishment of debt	0		0
Gain (loss) on equity issuance		0	0	0
Interest income and expense, net of amounts capitalized	(5)	(9)	(6)	(21)
Derivative gain	0	0	0	0
Equity in subsidiary earnings (loss)	(3,202)	(12,794)	(10,712)	(10,715)
Other	(182)	(80)	(619)	(192)
Total other income (expense)	(3,389)	(12,883)	(11,337)	(10,928)
Income (loss) before income taxes	4,897	(8,865)	11,975	8,024
Income tax expense (benefit)	5	0	14	0
Net income (loss)	4,892	(8,865)	11,961	8,024
Comprehensive income (loss)	4,892	(8,865)	11,961	8,024
Reportable Legal Entities | Non- Guarantor Subsidiaries
Revenue:
Service revenues	14,678	11,501	38,775	31,615
Subscriber equipment sales	1,762	1,559	4,603	5,232
Total revenue	16,440	13,060	43,378	36,847
Operating expenses:
Cost of services (exclusive of depreciation, amortization, and accretion shown separately below)	2,819	8,442	7,966	14,039
Cost of subscriber equipment sales	1,354	1,203	3,306	3,896
Marketing, general and administrative	19,911	15,497	57,176	48,561
Depreciation, amortization and accretion	49	291	164	860
Total operating expenses	24,133	25,433	68,612	67,356
Income (loss) from operations	(7,693)	(12,373)	(25,234)	(30,509)
Other income (expense):
Loss on extinguishment of debt	0		0
Gain (loss) on equity issuance		0	(35)	0
Interest income and expense, net of amounts capitalized	(51)	36	(152)	(116)
Derivative gain	0	0	0	0
Equity in subsidiary earnings (loss)	0	0	0	0
Other	471	284	475	888
Total other income (expense)	420	320	288	772
Income (loss) before income taxes	(7,273)	(12,053)	(24,946)	(29,737)
Income tax expense (benefit)	62	(6,303)	195	(6,562)
Net income (loss)	(7,335)	(5,750)	(25,141)	(23,175)
Comprehensive income (loss)	(8,243)	(5,659)	(26,905)	(24,662)
Eliminations
Revenue:
Service revenues	(18,790)	(21,074)	(52,604)	(47,709)
Subscriber equipment sales	(952)	(884)	(2,920)	(2,244)
Total revenue	(19,742)	(21,958)	(55,524)	(49,953)
Operating expenses:
Cost of services (exclusive of depreciation, amortization, and accretion shown separately below)	(1,487)	(7,785)	(3,995)	(9,872)
Cost of subscriber equipment sales	(951)	(882)	(2,918)	(2,238)
Marketing, general and administrative	(17,319)	(12,153)	(48,637)	(37,615)
Depreciation, amortization and accretion	0	(122)	0	(361)
Total operating expenses	(19,757)	(20,942)	(55,550)	(50,086)
Income (loss) from operations	15	(1,016)	26	133
Other income (expense):
Loss on extinguishment of debt	0		0
Gain (loss) on equity issuance		0	0	0
Interest income and expense, net of amounts capitalized	(3)	1	5	(8)
Derivative gain	0	0	0	0
Equity in subsidiary earnings (loss)	2,448	15,537	13,173	14,885
Other	(17)	93	(24)	141
Total other income (expense)	2,428	15,631	13,154	15,018
Income (loss) before income taxes	2,443	14,615	13,180	15,151
Income tax expense (benefit)	0	0	0	0
Net income (loss)	2,443	14,615	13,180	15,151
Comprehensive income (loss)	$ 2,449	$ 14,608	$ 13,177	$ 15,146