Revenue - Effects of ASC 606 Within Consolidated Statement of Operations (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								6 Months Ended		9 Months Ended		12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Jun. 30, 2018	Jun. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2018	Dec. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales	$ 138,234	$ 136,318	$ 127,073	$ 94,413	$ 131,476	$ 99,953	$ 100,922	$ 84,265					$ 496,038	$ 416,616
Cost of sales	126,213	117,510	109,006	84,540	115,981	86,702	88,443	74,497					437,269	365,623
Gross profit	12,021	18,808	18,067	9,873	15,495	13,251	12,479	9,768					58,769	50,993
Operating loss	(16,171)	(6,595)	(3,492)	(10,447)	(3,472)	(5,708)	(3,266)	(5,600)					(36,705)	(18,046)
(Loss) income before taxes	(9,655)	(18,701)	(11,725)	(14,476)	(6,449)	(9,052)	(7,612)	(24,056)					(54,557)	(47,169)
Net loss	$ (9,898)	$ (18,819)	$ (11,805)	$ (14,204)	(6,129)	(9,201)	(7,747)	(24,535)	$ (26,009)	$ (32,282)	$ (44,828)	$ (41,483)	(54,726)	(47,612)
Net loss available to common stockholders					$ (37,196)	$ (12,804)	$ (10,937)	$ (24,535)					$ (54,726)	$ (85,472)
Net loss per common share:
Basic (in dollars per share)	$ (0.53)	$ (1.01)	$ (0.63)	$ (0.77)	$ (2.22)	$ (0.94)	$ (0.80)	$ (2.23)					$ (2.94)	$ (6.20)
Diluted (in dollars per share)	$ (0.84)	$ (1.01)	$ (0.63)	$ (0.77)	$ (2.22)	$ (0.94)	$ (0.80)	$ (2.23)					$ (2.94)	$ (6.20)
Impact of ASC 606 | ASC 606
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales													$ (1,995)
Cost of sales													(573)
Gross profit													(1,422)
Operating loss													(1,422)
(Loss) income before taxes													(1,422)
Net loss													(1,422)
Net loss available to common stockholders													$ (1,422)
Net loss per common share:
Basic (in dollars per share)													$ (0.08)
Diluted (in dollars per share)													$ (0.08)
ASC 605
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net sales													$ 498,033
Cost of sales													437,842
Gross profit													60,191
Operating loss													(35,283)
(Loss) income before taxes													(53,135)
Net loss													(53,304)
Net loss available to common stockholders													$ (53,304)
Net loss per common share:
Basic (in dollars per share)													$ (2.86)
Diluted (in dollars per share)													$ (2.86)