Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Mar. 31, 2014
Business Acquisition, Contingent Consideration [Line Items]
Increased (decreased) in net loss resulted from change in discount rate			$ 6,400,000	$ 3,600,000
Increased (decreased) in net loss per share resulted from change in discount rate			$ 0.36	$ 0.22
Increase / decrease in contingent consideration liability and non-operating, non-cash gain (loss)		$ 27,132,000	$ (8,149,000)
Increase (decrease) in net loss per share		$ 1.37	$ (0.46)
Estimated fair value of financing obligations		$ 52,151,000	$ 52,075,000
Book values of financing obligations		$ 67,967,000	63,767,000
Maturity period of highly liquid investments		Three months or less
Interest reserve			2,757,000		$ 6,890,000
Impairment of property and equipment		$ 8,591,000	0
Additional cost of goods sold related to inventory		1,229,000
Prepayments to supplier for lower housing assembly		$ 1,024,000
Inventory impairment charges			$ 0
Uncertain tax position recognition likelihood percentage		50.00%
Allegro stockholders [Member]
Business Acquisition, Contingent Consideration [Line Items]
Payments To Former Allegro Stockholders	$ 900,000
Maximum [Member]
Business Acquisition, Contingent Consideration [Line Items]
Cash flow discount rate			20.00%	18.00%
Minimum [Member]
Business Acquisition, Contingent Consideration [Line Items]
Cash flow discount rate			16.50%	16.50%